Document:

EX-10.2

 Exhibit 10.2 

XTERA COMMUNICATIONS, INC. 

1999 STOCK PLAN 
 As
Amended Through January 5, 2001 
 1. Purposes of the Plan. The purposes of this Stock Plan are to attract and retain the
best available personnel for positions of substantial responsibility, to provide additional incentive to Employees, Directors and Consultants and to promote the success of the Company’s business. Options granted under the Plan may be Incentive
Stock Options or Nonstatutory Stock Options, as determined by the Administrator at the time of grant. Stock Purchase Rights may also be granted under the Plan. 

2. Definitions. As used herein, the following definitions shall apply: 

(a) “Administrator” means the Board or any of its Committees as shall be administering the Plan in accordance with
Section 4 hereof. 
 (b) “Applicable Laws” means the requirements relating to the administration of stock option plans
under U.S. state corporate laws, U.S. federal and state securities laws, the Code, any stock exchange or quotation system on which the Common Stock is listed or quoted and the applicable laws of any other country or jurisdiction where Options or
Stock Purchase Rights are granted under the Plan. 
 (c) “Board” means the Board of Directors of the Company. 

(d) “Code” means the Internal Revenue Code of 1986, as amended. 

(e) “Committee” means a committee of Directors appointed by the Board in accordance with Section 4 hereof. 

(f) “Common Stock” means the Common Stock of the Company. 

(g) “Company” means Xtera Communications, Inc., a Delaware corporation. 

(h) “Consultant” means any person who is engaged by the Company or any Parent or Subsidiary to render consulting or advisory
services to such entity. 
 (i) “Director” means a member of the Board of Directors of the Company. 

(j) “Disability” means total and permanent disability as defined in Section 22(e)(3) of the Code. 

(k) “Employee” means any person, including Officers and Directors, employed by the Company or any Parent or Subsidiary of the
Company. A Service Provider shall not cease to be an Employee in the case of (i) any leave of absence approved by the Company or (ii) transfers between locations of the Company or between the Company, its Parent, any Subsidiary, or any
successor. For purposes of Incentive Stock Options, no such 

  
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leave may exceed ninety days, unless reemployment upon expiration of such leave is guaranteed by statute or contract. If reemployment upon expiration of a leave of absence approved by the Company
is not so guaranteed, on the 181st day of such leave any Incentive Stock Option held by the Optionee shall cease to be treated as an Incentive Stock Option and shall be treated for tax purposes as a Nonstatutory Stock Option. Neither service as a
Director nor payment of a director’s fee by the Company shall be sufficient to constitute “employment” by the Company. 
 (l)
“Exchange Act” means the Securities Exchange Act of 1934, as amended. 
 (m) “Fair Market Value” means, as
of any date, the value of Common Stock determined as follows: 
 (i) If the Common Stock is listed on any established stock exchange or a
national market system, including without limitation the Nasdaq National Market or The Nasdaq SmallCap Market of The Nasdaq Stock Market, its Fair Market Value shall be the closing sales price for such stock (or the closing bid, if no sales were
reported) as quoted on such exchange or system for the last market trading day prior to the time of determination, as reported in The Wall Street Journal or such other source as the Administrator deems reliable; 

(ii) If the Common Stock is regularly quoted by a recognized securities dealer but selling prices are not reported, its Fair Market Value
shall be the mean between the high bid and low asked prices for the Common Stock on the last market trading day prior to the day of determination; or 

(iii) In the absence of an established market for the Common Stock, the Fair Market Value thereof shall be determined in good faith by the
Administrator. 
 (n) “Incentive Stock Option” means an Option intended to qualify as an incentive stock option within the
meaning of Section 422 of the Code. 
 (o) “Nonstatutory Stock Option” means an Option not intended to qualify as an
Incentive Stock Option. 
 (p) “Officer” means a person who is an officer of the Company within the meaning of
Section 16 of the Exchange Act and the rules and regulations promulgated thereunder. 
 (q) “Option” means a stock
option granted pursuant to the Plan. 
 (r) “Option Agreement” means a written or electronic agreement between the Company
and an Optionee evidencing the terms and conditions of an individual Option grant. The Option Agreement is subject to the terms and conditions of the Plan. 

(s) “Option Exchange Program” means a program whereby outstanding Options are exchanged for Options with a lower exercise
price. 
 (t) “Optioned Stock” means the Common Stock subject to an Option or a Stock Purchase Right. 

  
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 (u) “Optionee” means the holder of an outstanding Option or Stock Purchase Right
granted under the Plan. 
 (v) “Parent” means a “parent corporation,” whether now or hereafter existing, as
defined in Section 424(e) of the Code. 
 (w) “Plan” means this 1999 Stock Plan. 

(x) “Restricted Stock” means shares of Common Stock acquired pursuant to a grant of a Stock Purchase Right under
Section 11 below. 
 (y) “Section 16(b)” means Section 16(b) of the Securities Exchange Act of 1934, as amended.

 (z) “Service Provider” means an Employee, Director or Consultant. 

(aa) “Share” means a share of the Common Stock, as adjusted in accordance with Section 12 below. 

(bb) “Stock Purchase Right” means a right to purchase Common Stock pursuant to Section 11 below. 

(cc) “Subsidiary” means a “subsidiary corporation,” whether now or hereafter existing, as defined in
Section 424(f) of the Code. 
 3. Stock Subject to the Plan. Subject to the provisions of Section 12 of the Plan, the
maximum aggregate number of Shares which may be subject to option and sold under the Plan is 39,789,525 Shares. The Shares may be authorized but unissued, or reacquired Common Stock. 

If an Option or Stock Purchase Right expires or becomes unexercisable without having been exercised in full, or is surrendered pursuant to an
Option Exchange Program, the unpurchased Shares which were subject thereto shall become available for future grant or sale under the Plan (unless the Plan has terminated). However, Shares that have actually been issued under the Plan, upon exercise
of either an Option or Stock Purchase Right, shall not be returned to the Plan and shall not become available for future distribution under the Plan, except that if Shares of Restricted Stock are repurchased by the Company at their original purchase
price, such Shares shall become available for future grant under the Plan. 
 4. Administration of the Plan. 

(a) Administrator. The Plan shall be administered by the Board or a Committee appointed by the Board, which Committee shall be
constituted to comply with Applicable Laws. 

  
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 (b) Powers of the Administrator. Subject to the provisions of the Plan and, in the case of
a Committee, the specific duties delegated by the Board to such Committee, and subject to the approval of any relevant authorities, the Administrator shall have the authority in its discretion: 

(i) to determine the Fair Market Value; 

(ii) to select the Service Providers to whom Options and Stock Purchase Rights may from time to time be granted hereunder; 

(iii) to determine the number of Shares to be covered by each such award granted hereunder; 

(iv) to approve forms of agreement for use under the Plan; 

(v) to determine the terms and conditions, of any Option or Stock Purchase Right granted hereunder. Such terms and conditions include, but
are not limited to, the exercise price, the time or times when Options or Stock Purchase Rights may be exercised (which may be based on performance criteria), any vesting acceleration or waiver of forfeiture restrictions, and any restriction or
limitation regarding any Option or Stock Purchase Right or the Common Stock relating thereto, based in each case on such factors as the Administrator, in its sole discretion, shall determine; 

(vi) to determine whether and under what circumstances an Option may be settled in cash under subsection 9(e) instead of Common Stock; 

(vii) to reduce the exercise price of any Option to the then current Fair Market Value if the Fair Market Value of the Common Stock covered
by such Option has declined since the date the Option was granted; 
 (viii) to initiate an Option Exchange Program; 

(ix) to prescribe, amend and rescind rules and regulations relating to the Plan, including rules and regulations relating to sub-plans
established for the purpose of qualifying for preferred tax treatment under foreign tax laws; 
 (x) to allow Optionees to satisfy
withholding tax obligations by electing to have the Company withhold from the Shares to be issued upon exercise of an Option or Stock Purchase Right that number of Shares having a Fair Market Value equal to the amount required to be withheld. The
Fair Market Value of the Shares to be withheld shall be determined on the date that the amount of tax to be withheld is to be determined. All elections by Optionees to have Shares withheld for this purpose shall be made in such form and under such
conditions as the Administrator may deem necessary or advisable; and 
 (xi) to construe and interpret the terms of the Plan and awards
granted pursuant to the Plan. 
 (c) Effect of Administrator’s Decision. All decisions, determinations and interpretations of
the Administrator shall be final and binding on all Optionees. 

  
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 5. Eligibility. 

(a) Nonstatutory Stock Options and Stock Purchase Rights may be granted to Service Providers. Incentive Stock Options may be granted only to
Employees. 
 (b) Each Option shall be designated in the Option Agreement as either an Incentive Stock Option or a Nonstatutory Stock
Option. However, notwithstanding such designation, to the extent that the aggregate Fair Market Value of the Shares with respect to which Incentive Stock Options are exercisable for the first time by the Optionee during any calendar year (under all
plans of the Company and any Parent or Subsidiary) exceeds $100,000, such Options shall be treated as Nonstatutory Stock Options. For purposes of this Section 5(b), Incentive Stock Options shall be taken into account in the order in which they
were granted. The Fair Market Value of the Shares shall be determined as of the time the Option with respect to such Shares is granted. 

(c) Neither the Plan nor any Option or Stock Purchase Right shall confer upon any Optionee any right with respect to continuing the
Optionee’s relationship as a Service Provider with the Company, nor shall it interfere in any way with his or her right or the Company’s right to terminate such relationship at any time, with or without cause. 

6. Term of Plan. The Plan shall become effective upon its adoption by the Board. It shall continue in effect for a term of ten
(10) years unless sooner terminated under Section 14 of the Plan. 
 7. Term of Option. The term of each Option shall be
stated in the Option Agreement; provided, however, that the term shall be no more than ten (10) years from the date of grant thereof. In the case of an Incentive Stock Option granted to an Optionee who, at the time the Option is
granted, owns stock representing more than ten percent (10%) of the voting power of all classes of stock of the Company or any Parent or Subsidiary, the term of the Option shall be five (5) years from the date of grant or such shorter term
as may be provided in the Option Agreement. 
 8. Option Exercise Price and Consideration. 

(a) The per share exercise price for the Shares to be issued upon exercise of an Option shall be such price as is determined by the
Administrator, but shall be subject to the following: 
 (i) In the case of an Incentive Stock Option 

(A) granted to an Employee who, at the time of grant of such Option, owns stock representing more than ten percent (10%) of the voting
power of all classes of stock of the Company or any Parent or Subsidiary, the exercise price shall be no less than 110% of the Fair Market Value per Share on the date of grant. 

(B) granted to any other Employee, the per Share exercise price shall be no less than 100% of the Fair Market Value per Share on the date of
grant. 

  
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 (ii) In the case of a Nonstatutory Stock Option 

(A) granted to a Service Provider who, at the time of grant of such Option, owns stock representing more than ten percent (10%) of the
voting power of all classes of stock of the Company or any Parent or Subsidiary, the exercise price shall be no less than 110% of the Fair Market Value per Share on the date of grant. 

(B) granted to any other Service Provider, the per Share exercise price shall be no less than 85% of the Fair Market Value per Share on the
date of grant. 
 (iii) Notwithstanding the foregoing, Options may be granted with a per Share exercise price other than as required above
pursuant to a merger or other corporate transaction. 
 (b) The consideration to be paid for the Shares to be issued upon exercise of an
Option, including the method of payment, shall be determined by the Administrator (and, in the case of an Incentive Stock Option, shall be determined at the time of grant). Such consideration may consist of (1) cash, (2) check,
(3) promissory note, (4) other Shares which (x) in the case of Shares acquired upon exercise of an Option, have been owned by the Optionee for more than six months on the date of surrender, and (y) have a Fair Market Value on the
date of surrender equal to the aggregate exercise price of the Shares as to which such Option shall be exercised, (5) consideration received by the Company under a cashless exercise program implemented by the Company in connection with the
Plan, or (6) any combination of the foregoing methods of payment. In making its determination as to the type of consideration to accept, the Administrator shall consider if acceptance of such consideration may be reasonably expected to benefit
the Company. 
 9. Exercise of Option. 

(a) Procedure for Exercise; Rights as a Stockholder. Any Option granted hereunder shall be exercisable according to the terms hereof at
such times and under such conditions as determined by the Administrator and set forth in the Option Agreement. Except in the case of Options granted to Officers, Directors and Consultants, Options shall become exercisable at a rate of no less than
20% per year over five (5) years from the date the Options are granted. Unless the Administrator provides otherwise, vesting of Options granted hereunder shall be tolled during any unpaid leave of absence. An Option may not be exercised
for a fraction of a Share. 
 An Option shall be deemed exercised when the Company receives: (i) written or electronic notice of
exercise (in accordance with the Option Agreement) from the person entitled to exercise the Option, and (ii) full payment for the Shares with respect to which the Option is exercised. Full payment may consist of any consideration and method of
payment authorized by the Administrator and permitted by the Option Agreement and the Plan. Shares issued upon exercise of an Option shall be issued in the name of the Optionee or, if requested by the Optionee, in the name of the Optionee and his or
her spouse. Until the Shares are issued (as 

  
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evidenced by the appropriate entry on the books of the Company or of a duly authorized transfer agent of the Company), no right to vote or receive dividends or any other rights as a Stockholder
shall exist with respect to the Shares, notwithstanding the exercise of the Option. The Company shall issue (or cause to be issued) such Shares promptly after the Option is exercised. No adjustment will be made for a dividend or other right for
which the record date is prior to the date the Shares are issued, except as provided in Section 12 of the Plan. 
 Exercise of an
Option in any manner shall result in a decrease in the number of Shares thereafter available, both for purposes of the Plan and for sale under the Option, by the number of Shares as to which the Option is exercised. 

(b) Termination of Relationship as a Service Provider. If an Optionee ceases to be a Service Provider, such Optionee may exercise his
or her Option within such period of time as is specified in the Option Agreement (of at least thirty (30) days) to the extent that the Option is vested on the date of termination (but in no event later than the expiration of the term of the
Option as set forth in the Option Agreement). In the absence of a specified time in the Option Agreement, the Option shall remain exercisable for three (3) months following the Optionee’s termination. If, on the date of termination, the
Optionee is not vested as to his or her entire Option, the Shares covered by the unvested portion of the Option shall revert to the Plan. If, after termination, the Optionee does not exercise his or her Option within the time specified by the
Administrator, the Option shall terminate, and the Shares covered by such Option shall revert to the Plan. 
 (c) Disability of
Optionee. If an Optionee ceases to be a Service Provider as a result of the Optionee’s Disability, the Optionee may exercise his or her Option within such period of time as is specified in the Option Agreement (of at least six
(6) months) to the extent the Option is vested on the date of termination (but in no event later than the expiration of the term of such Option as set forth in the Option Agreement). In the absence of a specified time in the Option Agreement,
the Option shall remain exercisable for twelve (12) months following the Optionee’s termination. If, on the date of termination, the Optionee is not vested as to his or her entire Option, the Shares covered by the unvested portion of the
Option shall revert to the Plan. If, after termination, the Optionee does not exercise his or her Option within the time specified herein, the Option shall terminate, and the Shares covered by such Option shall revert to the Plan. 

(d) Death of Optionee. If an Optionee dies while a Service Provider, the Option may be exercised within such period of time as is
specified in the Option Agreement (of at least six (6) months) to the extent that the Option is vested on the date of death (but in no event later than the expiration of the term of such Option as set forth in the Option Agreement) by the
Optionee’s estate or by a person who acquires the right to exercise the Option by bequest or inheritance. In the absence of a specified time in the Option Agreement, the Option shall remain exercisable for twelve (12) months following the
Optionee’s termination. If, at the time of death, the Optionee is not vested as to the entire Option, the Shares covered by the unvested portion of the Option shall immediately revert to the Plan. If the Option is not so exercised within the
time specified herein, the Option shall terminate, and the Shares covered by such Option shall revert to the Plan. 
 (e) Buyout
Provisions. The Administrator may at any time offer to buy out for a payment in cash or Shares, an Option previously granted, based on such terms and conditions as the Administrator shall establish and communicate to the Optionee at the time
that such offer is made. 

  
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 10. Non-Transferability of Options and Stock Purchase Rights. The Options and Stock
Purchase Rights may not be sold, pledged, assigned, hypothecated, transferred, or disposed of in any manner other than by will or by the laws of descent or distribution and may be exercised, during the lifetime of the Optionee, only by the Optionee.

 11. Stock Purchase Rights. 

(a) Rights to Purchase. Stock Purchase Rights may be issued either alone, in addition to, or in tandem with other awards granted under
the Plan and/or cash awards made outside of the Plan. After the Administrator determines that it will offer Stock Purchase Rights under the Plan, it shall advise the offeree in writing or electronically of the terms, conditions and restrictions
related to the offer, including the number of Shares that such person shall be entitled to purchase, the price to be paid, and the time within which such person must accept such offer. The terms of the offer shall comply in all respects with
Section 260.140.42 of Title 10 of the California Code of Regulations. The offer shall be accepted by execution of a Restricted Stock purchase agreement in the form determined by the Administrator. 

(b) Repurchase Option. Unless the Administrator determines otherwise, the Restricted Stock purchase agreement shall grant the Company a
repurchase option exercisable upon the voluntary or involuntary termination of the purchaser’s service with the Company for any reason (including death or disability). The purchase price for Shares repurchased pursuant to the Restricted Stock
purchase agreement shall be the original price paid by the purchaser and may be paid by cancellation of any indebtedness of the purchaser to the Company. The repurchase option shall lapse at such rate as the Administrator may determine. Except with
respect to Shares purchased by Officers, Directors and Consultants, the repurchase option shall in no case lapse at a rate of less than 20% per year over five (5) years from the date of purchase. 

(c) Other Provisions. The Restricted Stock purchase agreement shall contain such other terms, provisions and conditions not
inconsistent with the Plan as may be determined by the Administrator in its sole discretion. 
 (d) Rights as a Stockholder. Once the
Stock Purchase Right is exercised, the purchaser shall have rights equivalent to those of a Stockholder and shall be a Stockholder when his or her purchase is entered upon the records of the duly authorized transfer agent of the Company. No
adjustment shall be made for a dividend or other right for which the record date is prior to the date the Stock Purchase Right is exercised, except as provided in Section 12 of the Plan. 

12. Adjustments Upon Changes in Capitalization, Merger or Asset Sale. 

(a) Changes in Capitalization. Subject to any required action by the Stockholders of the Company, the number of shares of Common Stock
covered by each outstanding Option or Stock Purchase Right, and the number of shares of Common Stock which 

  
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have been authorized for issuance under the Plan but as to which no Options or Stock Purchase Rights have yet been granted or which have been returned to the Plan upon cancellation or expiration
of an Option or Stock Purchase Right, as well as the price per share of Common Stock covered by each such outstanding Option or Stock Purchase Right, shall be proportionately adjusted for any increase or decrease in the number of issued shares of
Common Stock resulting from a stock split, reverse stock split, stock dividend, combination or reclassification of the Common Stock, or any other increase or decrease in the number of issued shares of Common Stock effected without receipt of
consideration by the Company. The conversion of any convertible securities of the Company shall not be deemed to have been “effected without receipt of consideration.” Such adjustment shall be made by the Board, whose determination in that
respect shall be final, binding and conclusive. Except as expressly provided herein, no issuance by the Company of shares of stock of any class, or securities convertible into shares of stock of any class, shall affect, and no adjustment by reason
thereof shall be made with respect to, the number or price of shares of Common Stock subject to an Option or Stock Purchase Right. 
 (b)
Dissolution or Liquidation. In the event of the proposed dissolution or liquidation of the Company, the Administrator shall notify each Optionee as soon as practicable prior to the effective date of such proposed transaction. The
Administrator in its discretion may provide for an Optionee to have the right to exercise his or her Option or Stock Purchase Right until fifteen (15) days prior to such transaction as to all of the Optioned Stock covered thereby, including
Shares as to which the Option or Stock Purchase Right would not otherwise be exercisable. In addition, the Administrator may provide that any Company repurchase option applicable to any Shares purchased upon exercise of an Option or Stock Purchase
Right shall lapse as to all such Shares, provided the proposed dissolution or liquidation takes place at the time and in the manner contemplated. To the extent it has not been previously exercised, an Option or Stock Purchase Right will terminate
immediately prior to the consummation of such proposed action. 
 (c) Merger or Asset Sale. In the event of a merger of the Company
with or into another corporation, or the sale of substantially all of the assets of the Company, each outstanding Option and Stock Purchase Right shall be assumed or an equivalent option or right substituted by the successor corporation or a Parent
or Subsidiary of the successor corporation. In the event that the successor corporation refuses to assume or substitute for the Option or Stock Purchase Right, the Optionee shall fully vest in and have the right to exercise the Option or Stock
Purchase Right as to all of the Optioned Stock, including Shares as to which it would not otherwise be vested or exercisable. If an Option or Stock Purchase Right becomes fully vested and exercisable in lieu of assumption or substitution in the
event of a merger or sale of assets, the Administrator shall notify the Optionee in writing or electronically that the Option or Stock Purchase Right shall be fully exercisable for a period of fifteen (15) days from the date of such notice, and
the Option or Stock Purchase Right shall terminate upon the expiration of such period. For the purposes of this paragraph, the Option or Stock Purchase Right shall be considered assumed if, following the merger or sale of assets, the option or right
confers the right to purchase or receive, for each Share of Optioned Stock subject to the Option or Stock Purchase Right immediately prior to the merger or sale of assets, the consideration (whether stock, cash, or other securities or property)
received in the merger or sale of assets by holders of Common Stock for each Share held on the effective date of the transaction (and if holders were offered a choice of consideration, the type of consideration chosen by the holders of a majority of
the outstanding 

  
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Shares); provided, however, that if such consideration received in the merger or sale of assets is not solely common stock of the successor corporation or its Parent, the
Administrator may, with the consent of the successor corporation, provide for the consideration to be received upon the exercise of the Option or Stock Purchase Right, for each Share of Optioned Stock subject to the Option or Stock Purchase Right,
to be solely common stock of the successor corporation or its Parent equal in fair market value to the per share consideration received by holders of Common Stock in the merger or sale of assets. 

13. Time of Granting Options and Stock Purchase Rights. The date of grant of an Option or Stock Purchase Right shall, for all purposes,
be the date on which the Administrator makes the determination granting such Option or Stock Purchase Right, or such other date as is determined by the Administrator. Notice of the determination shall be given to each Service Provider to whom an
Option or Stock Purchase Right is so granted within a reasonable time after the date of such grant. 
 14. Amendment and Termination of
the Plan. 
 (a) Amendment and Termination. The Board may at any time amend, alter, suspend or terminate the Plan. 

(b) Stockholder Approval. The Board shall obtain Stockholder approval of any Plan amendment to the extent necessary and desirable to
comply with Applicable Laws. 
 (c) Effect of Amendment or Termination. No amendment, alteration, suspension or termination of the
Plan shall impair the rights of any Optionee, unless mutually agreed otherwise between the Optionee and the Administrator, which agreement must be in writing and signed by the Optionee and the Company. Termination of the Plan shall not affect the
Administrator’s ability to exercise the powers granted to it hereunder with respect to Options granted under the Plan prior to the date of such termination. 

15. Conditions Upon Issuance of Shares. 

(a) Legal Compliance. Shares shall not be issued pursuant to the exercise of an Option unless the exercise of such Option and the
issuance and delivery of such Shares shall comply with Applicable Laws and shall be further subject to the approval of counsel for the Company with respect to such compliance. 

(b) Investment Representations. As a condition to the exercise of an Option, the Administrator may require the person exercising such
Option to represent and warrant at the time of any such exercise that the Shares are being purchased only for investment and without any present intention to sell or distribute such Shares if, in the opinion of counsel for the Company, such a
representation is required. 
 16. Inability to Obtain Authority. The inability of the Company to obtain authority from any
regulatory body having jurisdiction, which authority is deemed by the Company’s counsel to be necessary to the lawful issuance and sale of any Shares hereunder, shall relieve the Company of any liability in respect of the failure to issue or
sell such Shares as to which such requisite authority shall not have been obtained. 

  
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 17. Reservation of Shares. The Company, during the term of this Plan, shall at all times
reserve and keep available such number of Shares as shall be sufficient to satisfy the requirements of the Plan. 
 18. Stockholder
Approval. The Plan shall be subject to approval by the stockholders of the Company within twelve (12) months after the date the Plan is adopted. Such stockholder approval shall be obtained in the degree and manner required under Applicable
Laws. 
 19. Information to Optionees and Purchasers. The Company shall provide to each Optionee and to each individual who acquires
Shares pursuant to the Plan, not less frequently than annually during the period such Optionee or purchaser has one or more Options or Stock Purchase Rights outstanding, and, in the case of an individual who acquires Shares pursuant to the Plan,
during the period such individual owns such Shares, copies of annual financial statements. The Company shall not be required to provide such statements to key employees whose duties in connection with the Company assure their access to equivalent
information. 

  
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 XTERA COMMUNICATIONS, INC. 

1999 STOCK PLAN 
 STOCK
OPTION AGREEMENT — EARLY EXERCISE 
 Unless otherwise defined herein, the terms defined in the Plan shall have the same defined
meanings in this Option Agreement. 
  

	I.	NOTICE OF STOCK OPTION GRANT 

 «Name» 

«Address» 
 «City» «State»
«Zip» 
 You have been granted an option to purchase Common Stock of the Company, subject to the terms and conditions of the
Plan and this Option Agreement, as follows: 
  

					
	Grant Number	 	 «GrantNo»

		
	Date of Grant	 	 «GrantDate»

		
	Vesting Commencement Date	 	 «VCD»

		
	Exercise Price per Share	 	 $«SharePrice»

		
	Total Number of Shares Granted	 	 «Shares»

		
	Total Exercise Price	 	 $«Total Price»

			
	Type of Option:	 	 «ISO»
	  	Incentive Stock Option
			
		 	 «NSO»
	  	Nonstatutory Stock Option
		
	Term/Expiration Date:	 	 «Expiration»

 Exercise and Vesting Schedule: 

This Option shall be exercisable, in whole or in part, according to the following vesting schedule: 

25% of the Shares subject to the Option shall vest on the date that is twelve months following the Vesting Commencement Date, and 1/48 of the
Shares subject to the Option shall vest at the end of each month thereafter, subject to the Optionee’s continuing to be a Service Provider on such dates. 

 Termination Period: 

This Option may be exercised, to the extent it is then vested, for three months after Optionee ceases to be a Service Provider. Upon death or
Disability of the Optionee, this Option may be exercised, to the extent it is then vested, for one year after Optionee ceases to be Service Provider. In no event shall this Option be exercised later than the Term/Expiration Date as provided above.

  

	II.	AGREEMENT 

 1. Grant of Option. The Plan Administrator of the Company
hereby grants to the Optionee named in the Notice of Grant (the “Optionee”), an option (the “Option”) to purchase the number of Shares set forth in the Notice of Grant, at the exercise price per Share set forth in the Notice of
Grant (the “Exercise Price”), and subject to the terms and conditions of the Plan, which is incorporated herein by reference. Subject to Section 14(c) of the Plan, in the event of a conflict between the terms and conditions of the
Plan and this Option Agreement, the terms and conditions of the Plan shall prevail. 
 If designated in the Notice of Grant as an Incentive
Stock Option (“ISO”), this Option is intended to qualify as an Incentive Stock Option as defined in Section 422 of the Code. Nevertheless, to the extent that it exceeds the $100,000 rule of Code Section 422(d), this Option shall
be treated as a Nonstatutory Stock Option (“NSO”). 
 2. Exercise of Option. This Option shall be exercisable during its
term in accordance with the provisions of Section 9 of the Plan as follows: 
 (a) Right to Exercise. 

(i) Subject to subsections 2(a)(ii) and 2(a)(iii) below, this Option shall be exercisable cumulatively according to the vesting schedule set
forth in the Notice of Grant. Alternatively, at the election of the Optionee, this option may be exercised in whole or in part at any time as to Shares that have not yet vested. For purposes of this Stock Option Agreement, Shares subject to the
Option shall vest based on continued employment of Optionee with the Company. Vested Shares shall not be subject to the Company’s repurchase right (as set forth in the Restricted Stock Purchase Agreement, attached hereto as Exhibit C-1).

 (ii) As a condition to exercising this Option for unvested Shares, the Optionee shall execute the Restricted Stock Purchase Agreement.

 (iii) This Option may not be exercised for a fraction of a Share. 

(b) Method of Exercise. This Option shall be exercisable by delivery of an exercise notice in the form attached as
Exhibit A (the “Exercise Notice”) which shall state the election to exercise the Option, the number of Shares with respect to which the Option is being exercised, and such other representations and agreements as may be required
by the Company. The Exercise Notice shall be accompanied by payment of the aggregate Exercise Price as to all Exercised Shares. This Option shall be deemed to be exercised upon receipt by the Company of such fully executed Exercise Notice
accompanied by the aggregate Exercise Price. 

  
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 No Shares shall be issued pursuant to the exercise of an Option unless such issuance and such
exercise complies with Applicable Laws. Assuming such compliance, for income tax purposes the Shares shall be considered transferred to the Optionee on the date on which the Option is exercised with respect to such Shares. 

3. Optionee’s Representations. In the event the Shares have not been registered under the Securities Act of 1933, as amended, at
the time this Option is exercised, the Optionee shall, if required by the Company, concurrently with the exercise of all or any portion of this Option, deliver to the Company his or her Investment Representation Statement in the form attached hereto
as Exhibit B. 
 4. Lock-Up Period. Optionee hereby agrees that, if so requested by the Company or any representative of the
underwriters (the “Managing Underwriter”) in connection with any registration of the offering of any securities of the Company under the Securities Act, Optionee shall not sell or otherwise transfer any Shares or other securities of the
Company during the 180-day period (or such other period as may be requested in writing by the Managing Underwriter and agreed to in writing by the Company) (the “Market Standoff Period”) following the effective date of a registration
statement of the Company filed under the Securities Act. Such restriction shall apply only to the first registration statement of the Company to become effective under the Securities Act that includes securities to be sold on behalf of the Company
to the public in an underwritten public offering under the Securities Act. The Company may impose stop-transfer instructions with respect to securities subject to the foregoing restrictions until the end of such Market Standoff Period. 

5. Method of Payment. Payment of the aggregate Exercise Price shall be by any of the following, or a combination thereof, at the
election of the Optionee: 
 (a) cash; 

(b) check; 
 (c) consideration
received by the Company under a formal cashless exercise program adopted by the Company in connection with the Plan; or 
 (d) surrender of
other Shares which, (i) in the case of Shares acquired upon exercise of an option, have been owned by the Optionee for more than six (6) months on the date of surrender, and (ii) have a Fair Market Value on the date of surrender equal
to the aggregate Exercise Price of the Exercised Shares. 
 6. Restrictions on Exercise. This Option may not be exercised until such
time as the Plan has been approved by the shareholders of the Company, or if the issuance of such Shares upon such exercise or the method of payment of consideration for such shares would constitute a violation of any Applicable Law. 

7. Non-Transferability of Option. This Option may not be transferred in any manner otherwise than by will or by the laws of descent or
distribution and may be exercised during the lifetime of Optionee only by Optionee. The terms of the Plan and this Option Agreement shall be binding upon the executors, administrators, heirs, successors and assigns of the Optionee. 

  
 -3- 

 8. Term of Option. This Option may be exercised only within the term set out in the Notice
of Grant, and may be exercised during such term only in accordance with the Plan and the terms of this Option. 
 9. Tax
Consequences. Set forth below is a brief summary as of the date of this Option of some of the federal tax consequences of exercise of this Option and disposition of the Shares. THIS SUMMARY IS NECESSARILY INCOMPLETE, AND THE TAX LAWS AND
REGULATIONS ARE SUBJECT TO CHANGE. THE OPTIONEE SHOULD CONSULT A TAX ADVISER BEFORE EXERCISING THIS OPTION OR DISPOSING OF THE SHARES. 

(a) Exercise of ISO. If this Option qualifies as an ISO, there will be no regular federal income tax liability upon the exercise of the
Option, although the excess, if any, of the Fair Market Value of the Shares on the date of exercise over the Exercise Price will be treated as an adjustment to the alternative minimum tax for federal tax purposes and may subject the Optionee to the
alternative minimum tax in the year of exercise. 
 (b) Exercise of ISO Following Disability. If the Optionee ceases to be an
Employee as a result of a disability that is not a total and permanent disability as defined in Section 22(e)(3) of the Code, to the extent permitted on the date of termination, the Optionee must exercise an ISO within three months of such
termination for the ISO to be qualified as an ISO. 
 (c) Exercise of Nonstatutory Stock Option. There may be a regular federal
income tax liability upon the exercise of a Nonstatutory Stock Option. The Optionee will be treated as having received compensation income (taxable at ordinary income tax rates) equal to the excess, if any, of the Fair Market Value of the Shares on
the date of exercise over the Exercise Price. If Optionee is an Employee or a former Employee, the Company will be required to withhold from Optionee’s compensation or collect from Optionee and pay to the applicable taxing authorities an amount
in cash equal to a percentage of this compensation income at the time of exercise, and may refuse to honor the exercise and refuse to deliver Shares if such withholding amounts are not delivered at the time of exercise. 

(d) Disposition of Shares. In the case of an NSO, if Shares are held for at least one year, any gain realized on disposition of the
Shares will be treated as long-term capital gain for federal income tax purposes. In the case of an ISO, if Shares transferred pursuant to the Option are held for at least one year after exercise and at least two years after the Date of Grant, any
gain realized on disposition of the Shares will also be treated as long-term capital gain for federal income tax purposes. If Shares purchased under an ISO are disposed of within one year after exercise or two years after the Date of Grant, any gain
realized on such disposition will be treated as compensation income (taxable at ordinary income rates) to the extent of the difference between the Exercise Price and the lesser of (i) the Fair Market Value of the Shares on the date of exercise,
or (ii) the sale price of the Shares. Different rules may apply if the Shares are subject to a substantial risk of forfeiture (within the meaning of Section 83) at the time of purchase. Any additional gain will be taxed as capital gain,
short-term depending on the period that the ISO Shares were held. 

  
 -4- 

 (e) Notice of Disqualifying Disposition of ISO Shares. If the Option granted to Optionee
herein is an ISO, and if Optionee sells or otherwise disposes of any of the Shares acquired pursuant to the ISO on or before the later of (i) the date two years after the Date of Grant, or (ii) the date one year after the date of exercise,
the Optionee shall immediately notify the Company in writing of such disposition. Optionee agrees that Optionee may be subject to income tax withholding by the Company on the compensation income recognized by the Optionee. 

(f) Section 83(b) Election for Unvested Shares Purchased Pursuant to Options. With respect to the exercise of an Option for
unvested Shares, an election may be filed by the Optionee with the Internal Revenue Service, within 30 days of the purchase of the Shares, electing pursuant to Section 83(b) of the Code to be taxed currently on any difference between the
purchase price of the Shares and their Fair Market Value on the date of purchase. In the case of a Nonstatutory Stock Option, this will result in a recognition of taxable income to the Optionee on the date of exercise, measured by the excess, if
any, of the fair market value of the Shares, at the time the Option is exercised over the purchase price for the Shares. Absent such an election, taxable income will be measured and recognized by Optionee at the time or times on which the
Company’s Repurchase Option lapses. In the case of an Incentive Stock Option, such an election will result in a recognition of income to the Optionee for alternative minimum tax purposes on the date of exercise, measured by the excess, if any,
of the fair market value of the Shares, at the time the option is exercised, over the purchase price for the Shares. Absent such an election, alternative minimum taxable income will be measured and recognized by Optionee at the time or times on
which the Company’s Repurchase Option lapses. Optionee is strongly encouraged to seek the advice of his or her own tax consultants in connection with the purchase of the Shares and the advisability of filing of the Election under
Section 83(b) of the Code. A form of Election under Section 83(b) is attached hereto as Exhibit C-5 for reference. 

OPTIONEE ACKNOWLEDGES THAT IT IS OPTIONEE’S SOLE RESPONSIBILITY AND NOT THE COMPANY’S TO FILE TIMELY THE ELECTION UNDER SECTION
83(b), EVEN IF OPTIONEE REQUESTS THE COMPANY OR ITS REPRESENTATIVE TO MAKE THIS FILING ON OPTIONEE’S BEHALF. 
 10. Entire
Agreement; Governing Law. The Plan is incorporated herein by reference. The Plan and this Option Agreement constitute the entire agreement of the parties with respect to the subject matter hereof and supersede in their entirety all prior
undertakings and agreements of the Company and Optionee with respect to the subject matter hereof, and may not be modified adversely to the Optionee’s interest except by means of a writing signed by the Company and Optionee. This agreement is
governed by the internal substantive laws but not the choice of law rules of Texas. 
 11. No Guarantee of Continued Service.
OPTIONEE ACKNOWLEDGES AND AGREES THAT THE VESTING OF SHARES PURSUANT TO THE VESTING SCHEDULE HEREOF IS EARNED ONLY BY CONTINUING AS A SERVICE PROVIDER AT THE WILL OF THE COMPANY (NOT THROUGH THE ACT OF BEING HIRED, BEING GRANTED THIS OPTION OR
ACQUIRING SHARES HEREUNDER). OPTIONEE FURTHER ACKNOWLEDGES AND AGREES THAT THIS AGREEMENT, THE TRANSACTIONS CONTEMPLATED HEREUNDER AND THE VESTING SCHEDULE SET 

  
 -5- 

 
FORTH HEREIN DO NOT CONSTITUTE AN EXPRESS OR IMPLIED PROMISE OF CONTINUED ENGAGEMENT AS A SERVICE PROVIDER FOR THE VESTING PERIOD, FOR ANY PERIOD, OR AT ALL, AND SHALL NOT INTERFERE IN ANY WAY
WITH OPTIONEE’S RIGHT OR THE COMPANY’S RIGHT TO TERMINATE OPTIONEE’S RELATIONSHIP AS A SERVICE PROVIDER AT ANY TIME, WITH OR WITHOUT CAUSE. 

Optionee acknowledges receipt of a copy of the Plan and represents that he or she is familiar with the terms and provisions thereof, and
hereby accepts this Option subject to all of the terms and provisions thereof. Optionee has reviewed the Plan and this Option in their entirety, has had an opportunity to obtain the advice of counsel prior to executing this Option and fully
understands all provisions of the Option. Optionee hereby agrees to accept as binding, conclusive and final all decisions or interpretations of the Administrator upon any questions arising under the Plan or this Option. Optionee further agrees to
notify the Company upon any change in the residence address indicated below. 
  

					
	OPTIONEE:	 		 	XTERA COMMUNICATIONS, INC.
			
	  
	 		 	  

	Signature	 		 	By
			
	 «Name»
	 		 	  

	Print Name	 		 	Title
			
	 «Address»
	 		 	
			
	 «City», «State» «Zip»
	 		 	
	Residence Address	 		 	

  
 -6- 

 EXHIBIT A 

XTERA COMMUNICATIONS, INC. 

1999 STOCK PLAN 

EXERCISE NOTICE 
 Xtera Communications,
Inc. 
 500 W. Bethany Drive 
 Allen, TX 75013 

Attention: Corporate Secretary 
 1. Exercise
of Option. Effective as of today,             ,         , the undersigned (“Optionee”) hereby elects to exercise Optionee’s option
to purchase                  shares of the Common Stock (the “Shares”) of Xtera Communications, Inc. (the “Company”) under and pursuant to the
Company’s 1999 Stock Plan (the “Plan”) and the [    ] Incentive [    ] Nonstatutory Stock Option Agreement dated as of «GrantDate» (the “Option Agreement”). 

2. Delivery of Payment. Purchaser herewith delivers to the Company the full purchase price of the Shares, as set forth in the Option
Agreement. 
 3. Representations of Optionee. Optionee acknowledges that Optionee has received, read and understood the Plan and the
Option Agreement and agrees to abide by and be bound by their terms and conditions. 
 4. Rights as Shareholder. Until the issuance
of the Shares (as evidenced by the appropriate entry on the books of the Company or of a duly authorized transfer agent of the Company), no right to vote or receive dividends or any other rights as a shareholder shall exist with respect to the
Optioned Stock, notwithstanding the exercise of the Option. The Shares shall be issued to the Optionee as soon as practicable after the Option is exercised. No adjustment shall be made for a dividend or other right for which the record date is prior
to the date of issuance except as provided in Section 12 of the Plan. 
 5. Company’s Right of First Refusal. Before any
Shares held by Optionee or any transferee (either being sometimes referred to herein as the “Holder”) may be sold or otherwise transferred (including transfer by gift or operation of law), the Company or its assignee(s) shall have a right
of first refusal to purchase the Shares on the terms and conditions set forth in this Section (the “Right of First Refusal”). 

(a) Notice of Proposed Transfer. The Holder of the Shares shall deliver to the Company a written notice (the “Notice”)
stating: (i) the Holder’s bona fide intention to sell or otherwise transfer such Shares; (ii) the name of each proposed purchaser or other transferee (“Proposed Transferee”); (iii) the number of Shares to be transferred
to each Proposed Transferee; and (iv) the bona fide cash price or other consideration for which the Holder proposes to transfer the Shares (the “Offered Price”), and the Holder shall offer the Shares at the Offered Price to the
Company or its assignee(s). 

 (b) Exercise of Right of First Refusal. At any time within thirty (30) days after
receipt of the Notice, the Company and/or its assignee(s) may, by giving written notice to the Holder, elect to purchase all, but not less than all, of the Shares proposed to be transferred to any one or more of the Proposed Transferees, at the
purchase price determined in accordance with subsection (c) below. 
 (c) Purchase Price. The purchase price (“Purchase
Price”) for the Shares purchased by the Company or its assignee(s) under this Section shall be the Offered Price. If the Offered Price includes consideration other than cash, the cash equivalent value of the non-cash consideration shall be
determined by the Board of Directors of the Company in good faith. 
 (d) Payment. Payment of the Purchase Price shall be made, at
the option of the Company or its assignee(s), in cash (by check), by cancellation of all or a portion of any outstanding indebtedness of the Holder to the Company (or, in the case of repurchase by an assignee, to the assignee), or by any combination
thereof within 30 days after receipt of the Notice or in the manner and at the times set forth in the Notice. 
 (e) Holder’s Right
to Transfer. If all of the Shares proposed in the Notice to be transferred to a given Proposed Transferee are not purchased by the Company and/or its assignee(s) as provided in this Section, then the Holder may sell or otherwise transfer such
Shares to that Proposed Transferee at the Offered Price or at a higher price, provided that such sale or other transfer is consummated within 120 days after the date of the Notice, that any such sale or other transfer is effected in
accordance with any applicable securities laws and that the Proposed Transferee agrees in writing that the provisions of this Section shall continue to apply to the Shares in the hands of such Proposed Transferee. If the Shares described in the
Notice are not transferred to the Proposed Transferee within such period, a new Notice shall be given to the Company, and the Company and/or its assignees shall again be offered the Right of First Refusal before any Shares held by the Holder may be
sold or otherwise transferred. 
 (f) Exception for Certain Family Transfers. Anything to the contrary contained in this Section
notwithstanding, the transfer of any or all of the Shares during the Optionee’s lifetime or on the Optionee’s death by will or intestacy to the Optionee’s immediate family or a trust for the benefit of the Optionee’s immediate
family shall be exempt from the provisions of this Section. “Immediate Family” as used herein shall mean spouse, lineal descendant or antecedent, father, mother, brother or sister. In such case, the transferee or other recipient shall
receive and hold the Shares so transferred subject to the provisions of this Section, and there shall be no further transfer of such Shares except in accordance with the terms of this Section. 

(g) Termination of Right of First Refusal. The Right of First Refusal shall terminate as to any Shares upon the first sale of Common
Stock of the Company to the general public pursuant to a registration statement filed with and declared effective by the Securities and Exchange Commission under the Securities Act of 1933, as amended. 

6. Tax Consultation. Optionee understands that Optionee may suffer adverse tax consequences as a result of Optionee’s purchase or
disposition of the Shares. Optionee represents that Optionee has consulted with any tax consultants Optionee deems advisable in connection with the purchase or disposition of the Shares and that Optionee is not relying on the Company for any tax
advice. 

  
 -2- 

 7. Restrictive Legends and Stop-Transfer Orders. 

(a) Legends. Optionee understands and agrees that the Company shall cause the legends set forth below or legends substantially
equivalent thereto, to be placed upon any certificate(s) evidencing ownership of the Shares together with any other legends that may be required by the Company or by state or federal securities laws: 

THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 (THE “ACT”) AND MAY NOT BE OFFERED, SOLD
OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL REGISTERED UNDER THE ACT OR, IN THE OPINION OF COMPANY COUNSEL SATISFACTORY TO THE ISSUER OF THESE SECURITIES, SUCH OFFER, SALE OR TRANSFER, PLEDGE OR HYPOTHECATION IS IN COMPLIANCE
THEREWITH. 
 THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN RESTRICTIONS ON TRANSFER AND RIGHT OF FIRST REFUSAL OPTIONS
HELD BY THE ISSUER OR ITS ASSIGNEE(S) AS SET FORTH IN THE EXERCISE NOTICE BETWEEN THE ISSUER AND THE ORIGINAL HOLDER OF THESE SHARES, A COPY OF WHICH MAY BE OBTAINED AT THE PRINCIPAL OFFICE OF THE ISSUER. SUCH TRANSFER RESTRICTIONS AND RIGHT OF
FIRST REFUSAL ARE BINDING ON TRANSFEREES OF THESE SHARES. 
 (b) Stop-Transfer Notices. Optionee agrees that, in order to ensure
compliance with the restrictions referred to herein, the Company may issue appropriate “stop transfer” instructions to its transfer agent, if any, and that, if the Company transfers its own securities, it may make appropriate notations to
the same effect in its own records. 
 (c) Refusal to Transfer. The Company shall not be required (i) to transfer on its books
any Shares that have been sold or otherwise transferred in violation of any of the provisions of this Agreement or (ii) to treat as owner of such Shares or to accord the right to vote or pay dividends to any purchaser or other transferee to
whom such Shares shall have been so transferred. 
 8. Successors and Assigns. The Company may assign any of its rights under this
Agreement to single or multiple assignees, and this Agreement shall inure to the benefit of the successors and assigns of the Company. Subject to the restrictions on transfer herein set forth, this Agreement shall be binding upon Optionee and his or
her heirs, executors, administrators, successors and assigns. 
 9. Interpretation. Any dispute regarding the interpretation of this
Agreement shall be submitted by Optionee or by the Company forthwith to the Administrator which shall review such dispute at its next regular meeting. The resolution of such a dispute by the Administrator shall be final and binding on all parties.

  
 -3- 

 10. Governing Law; Severability. This Agreement is governed by the internal substantive
laws, but not the choice of law rules, of Texas. 
 11. Entire Agreement. The Plan and Option Agreement are incorporated herein by
reference. This Agreement, the Plan, the Restricted Stock Purchase Agreement, the Option Agreement and the Investment Representation Statement constitute the entire agreement of the parties with respect to the subject matter hereof and supersede in
their entirety all prior undertakings and agreements of the Company and Optionee with respect to the subject matter hereof, and may not be modified adversely to the Optionee’s interest except by means of a writing signed by the Company and
Optionee. 
  

					
	Submitted by:	 		 	Accepted by:
			
	OPTIONEE:	 		 	XTERA COMMUNICATIONS, INC.
			
	  
	 		 	  

	Signature	 		 	By
			
	 «Name»
	 		 	  

	Print Name	 		 	Its
			
	Address:	 		 	Address:
			
	 «Address»
	 		 	500 W. Bethany Drive
		 		 	Allen, TX 75013
	 «City», «State» «Zip»
	 		 	
		 		 	  

		 		 	Date Received

  
 -4- 

 EXHIBIT B 

INVESTMENT REPRESENTATION STATEMENT 
  

					
	OPTIONEE	 	:	    	«Name»
			
	COMPANY	 	:	    	XTERA COMMUNICATIONS, INC.
			
	SECURITY	 	:	    	COMMON STOCK
			
	AMOUNT	 	:	    	
			
	DATE	 	:	    	

 In connection with the purchase of the above-listed Securities, the undersigned Optionee represents to the
Company the following: 
 (a) Optionee is aware of the Company’s business affairs and financial condition and has acquired sufficient
information about the Company to reach an informed and knowledgeable decision to acquire the Securities. Optionee is acquiring these Securities for investment for Optionee’s own account only and not with a view to, or for resale in connection
with, any “distribution” thereof within the meaning of the Securities Act of 1933, as amended (the “Securities Act”). 

(b) Optionee acknowledges and understands that the Securities constitute “restricted securities” under the Securities Act and have
not been registered under the Securities Act in reliance upon a specific exemption therefrom, which exemption depends upon, among other things, the bona fide nature of Optionee’s investment intent as expressed herein. In this connection,
Optionee understands that, in the view of the Securities and Exchange Commission, the statutory basis for such exemption may be unavailable if Optionee’s representation was predicated solely upon a present intention to hold these Securities for
the minimum capital gains period specified under tax statutes, for a deferred sale, for or until an increase or decrease in the market price of the Securities, or for a period of one year or any other fixed period in the future. Optionee further
understands that the Securities must be held indefinitely unless they are subsequently registered under the Securities Act or an exemption from such registration is available. Optionee further acknowledges and understands that the Company is under
no obligation to register the Securities. Optionee understands that the certificate evidencing the Securities will be imprinted with a legend which prohibits the transfer of the Securities unless they are registered or such registration is not
required in the opinion of counsel satisfactory to the Company and any other legend required under applicable state securities laws. 
 (c)
Optionee is familiar with the provisions of Rule 701 and Rule 144, each promulgated under the Securities Act, which, in substance, permit limited public resale of “restricted securities” acquired, directly or indirectly from the issuer
thereof, in a non-public offering subject to the satisfaction of certain conditions. Rule 701 provides that if the issuer qualifies under Rule 701 at the time of the grant of the Option to the Optionee, the exercise will be exempt from registration
under the Securities Act. In the event the Company becomes subject 

 
to the reporting requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, ninety (90) days thereafter (or such longer period as any market stand-off agreement may
require) the Securities exempt under Rule 701 may be resold, subject to the satisfaction of certain of the conditions specified by Rule 144, including: (1) the resale being made through a broker in an unsolicited “broker’s
transaction” or in transactions directly with a market maker (as said term is defined under the Securities Exchange Act of 1934); and, in the case of an affiliate, (2) the availability of certain public information about the Company,
(3) the amount of Securities being sold during any three month period not exceeding the limitations specified in Rule 144(e), and (4) the timely filing of a Form 144, if applicable. 

In the event that the Company does not qualify under Rule 701 at the time of grant of the Option, then the Securities may be resold in certain
limited circumstances subject to the provisions of Rule 144, which requires the resale to occur not less than one year after the later of the date the Securities were sold by the Company or the date the Securities were sold by an affiliate of the
Company, within the meaning of Rule 144; and, in the case of acquisition of the Securities by an affiliate, or by a non-affiliate who subsequently holds the Securities less than two years, the satisfaction of the conditions set forth in sections
(1), (2), (3) and (4) of the paragraph immediately above. 
 (d) Optionee further understands that in the event all of the
applicable requirements of Rule 701 or 144 are not satisfied, registration under the Securities Act, compliance with Regulation A, or some other registration exemption will be required; and that, notwithstanding the fact that Rules 144 and 701 are
not exclusive, the Staff of the Securities and Exchange Commission has expressed its opinion that persons proposing to sell private placement securities other than in a registered offering and otherwise than pursuant to Rules 144 or 701 will have a
substantial burden of proof in establishing that an exemption from registration is available for such offers or sales, and that such persons and their respective brokers who participate in such transactions do so at their own risk. Optionee
understands that no assurances can be given that any such other registration exemption will be available in such event. 
  

	
	Signature of Optionee:
	
	  

 Date:             ,
         

  
 -2- 

 EXHIBIT C-1 

XTERA COMMUNICATIONS, INC. 

1999 STOCK PLAN 

RESTRICTED STOCK PURCHASE AGREEMENT 

THIS AGREEMENT is made between «Name» (the “Purchaser”) and Xtera Communications, Inc. (the “Company”) as of
            ,         . 
 RECITALS

 (1) Pursuant to the exercise of the stock option (grant number «GrantNo») granted to Purchaser under the Company’s
1999 Stock Plan (the “Plan”) and pursuant to the Stock Option Agreement (the “Option Agreement”) dated as of «GrantDate» by and between the Company and Purchaser with respect to such grant, which Plan and Option
Agreement are hereby incorporated by reference, Purchaser has elected to purchase                  of those shares which have not become vested under the vesting
schedule set forth in the Option Agreement (“Unvested Shares”). The Unvested Shares and the shares subject to the Option Agreement which have become vested are sometimes collectively referred to herein as the “Shares”. 

(2) As required by the Option Agreement, as a condition to Purchaser’s election to exercise the option, Purchaser must execute this
Restricted Stock Purchase Agreement, which sets forth the rights and obligations of the parties with respect to Shares acquired upon exercise of the Option. 

1. Repurchase Option. 

(a) If Purchaser’s status as a Service Provider is terminated for any reason, including for cause, death, and disability, the Company
shall have the right and option to purchase from Purchaser, or Purchaser’s personal representative, as the case may be, all of the Purchaser’s Unvested Shares as of the date of such termination at the lesser of the per share price
originally paid by the Purchaser for such Shares or the Fair Market Value (as defined in the Company’s 1999 Stock Plan) per Share as of the date of repurchase, in each case as adjusted for stock splits, stock dividends and similar events having
occurred since the grant date of the Option (the “Repurchase Option”). 
 (b) Upon the occurrence of a termination, the Company
may exercise its Repurchase Option by delivering personally or by registered mail, to Purchaser (or his transferee or legal representative, as the case may be), within ninety (90) days of the termination, a notice in writing indicating the
Company’s intention to exercise the Repurchase Option and setting forth a date for closing not later than thirty (30) days from the mailing of such notice. The closing shall take place at the Company’s office. At the closing, the
holder of the certificates for the Unvested Shares being transferred shall deliver the stock certificate or certificates evidencing the Unvested Shares, and the Company shall deliver the purchase price therefor. 

 (c) At its option, the Company may elect to make payment for the Unvested Shares to a bank
selected by the Company. The Company shall avail itself of this option by a notice in writing to Purchaser stating the name and address of the bank, date of closing, and waiving the closing at the Company’s office. 

(d) If the Company does not elect to exercise the Repurchase Option conferred above by giving the requisite notice within ninety
(90) days following the termination, the Repurchase Option shall terminate. 
 (e) The Repurchase Option shall terminate in accordance
with the Vesting Schedule in Optionee’s Option Agreement. 
 2. Transferability of the Shares; Escrow. 

(a) Purchaser hereby authorizes and directs the secretary of the Company, or such other person designated by the Company, to transfer the
Unvested Shares as to which the Repurchase Option has been exercised from Purchaser to the Company. 
 (b) To insure the availability for
delivery of Purchaser’s Unvested Shares upon repurchase by the Company pursuant to the Repurchase Option under Section 1, Purchaser hereby appoints the secretary, or any other person designated by the Company as escrow agent, as its
attorney-in-fact to sell, assign and transfer unto the Company, such Unvested Shares, if any, repurchased by the Company pursuant to the Repurchase Option and shall, upon execution of this Agreement, deliver and deposit with the secretary of the
Company, or such other person designated by the Company, the share certificates representing the Unvested Shares, together with the stock assignment duly endorsed in blank, attached hereto as Exhibit C-2. The Unvested Shares and stock
assignment shall be held by the secretary in escrow, pursuant to the Joint Escrow Instructions of the Company and Purchaser attached as Exhibit C-3 hereto, until the Company exercises its purchase right as provided in Section 1, until
such Unvested Shares are vested, or until such time as this Agreement no longer is in effect. As a further condition to the Company’s obligations under this Agreement, the spouse of the Purchaser, if any, shall execute and deliver to the
Company the Consent of Spouse attached hereto as Exhibit C-4. Upon vesting of the Unvested Shares, the escrow agent shall promptly deliver to the Purchaser the certificate or certificates representing such Shares in the escrow agent’s
possession belonging to the Purchaser, and the escrow agent shall be discharged of all further obligations hereunder; provided, however, that the escrow agent shall nevertheless retain such certificate or certificates as escrow agent
if so required pursuant to other restrictions imposed pursuant to this Agreement. 
 (c) The Company, or its designee, shall not be liable
for any act it may do or omit to do with respect to holding the Shares in escrow and while acting in good faith and in the exercise of its judgment. 

(d) Transfer or sale of the Shares is subject to restrictions on transfer imposed by any applicable state and federal securities laws. Any
transferee shall hold such Shares subject to all the provisions hereof and the Exercise Notice executed by the Purchaser with respect to any Unvested Shares purchased by Purchaser and shall acknowledge the same by signing a copy of this Agreement.

  
 -2- 

 3. Ownership, Voting Rights, Duties. This Agreement shall not affect in any way the
ownership, voting rights or other rights or duties of Purchaser, except as specifically provided herein. 
 4. Legends. The share
certificate evidencing the Shares issued hereunder shall be endorsed with the following legend (in addition to any legend required under applicable state securities laws): 

THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN RESTRICTIONS UPON TRANSFER AND RIGHTS OF REPURCHASE AS SET FORTH IN AN
AGREEMENT BETWEEN THE COMPANY AND THE STOCKHOLDER, A COPY OF WHICH IS ON FILE WITH THE SECRETARY OF THE COMPANY. 
 5. Adjustment for
Stock Split. All references to the number of Shares and the purchase price of the Shares in this Agreement shall be appropriately adjusted to reflect any stock split, stock dividend or other change in the Shares which may be made by the Company
after the date of this Agreement. 
 6. Notices. Notices required hereunder shall be given in person or by registered mail to the
address of Purchaser shown on the records of the Company, and to the Company at their respective principal executive offices. 
 7.
Survival of Terms. This Agreement shall apply to and bind Purchaser and the Company and their respective permitted assignees and transferees, heirs, legatees, executors, administrators and legal successors. 

8. Section 83(b) Election. Purchaser hereby acknowledges that he or she has been informed that, with respect to the exercise of an
Option for unvested Shares, an election may be filed by the Purchaser with the Internal Revenue Service, within 30 days of the purchase of the Shares, electing pursuant to Section 83(b) of the Code to be taxed currently on any difference
between the purchase price of the Shares and their Fair Market Value on the date of purchase. In the case of a Nonstatutory Stock Option, this will result in a recognition of taxable income to the Purchaser on the date of exercise, measured by the
excess, if any, of the fair market value of the Shares, at the time the Option is exercised over the purchase price for the Shares. Absent such an election, taxable income will be measured and recognized by Purchaser at the time or times on which
the Company’s Repurchase Option lapses. In the case of an Incentive Stock Option, such an election will result in a recognition of income to the Purchaser for alternative minimum tax purposes on the date of exercise, measured by the excess, if
any, of the fair market value of the Shares, at the time the option is exercised, over the purchase price for the Shares. Absent such an election, alternative minimum taxable income will be measured and recognized by Purchaser at the time or times
on which the Company’s Repurchase Option lapses. Purchaser is strongly encouraged to seek the advice of his or her own tax consultants in connection with the purchase of the Shares and the advisability of filing of the Election under
Section 83(b) of the Code. A form of Election under Section 83(b) is attached hereto as Exhibit C-5 for reference. 

  
 -3- 

 PURCHASER ACKNOWLEDGES THAT IT IS PURCHASER’S SOLE RESPONSIBILITY AND NOT THE COMPANY’S
TO FILE TIMELY THE ELECTION UNDER SECTION 83(b), EVEN IF PURCHASER REQUESTS THE COMPANY OR ITS REPRESENTATIVE TO MAKE THIS FILING ON PURCHASER’S BEHALF. 

9. Representations. Purchaser has reviewed with his own tax advisors the federal, state, local and foreign tax consequences of this
investment and the transactions contemplated by this Agreement. Purchaser is relying solely on such advisors and not on any statements or representations of the Company or any of its agents. Purchaser understands that he (and not the Company) shall
be responsible for his own tax liability that may arise as a result of this investment or the transactions contemplated by this Agreement. 

10. Governing Law. This Agreement shall be governed by the internal substantive laws, but not the choice of law rules, of Texas. 

Purchaser represents that he has read this Agreement and is familiar with its terms and provisions. Purchaser hereby agrees to accept as
binding, conclusive and final all decisions or interpretations of the Board upon any questions arising under this Agreement. 

  
 -4- 

 IN WITNESS WHEREOF, this Agreement is deemed made as of the date first set forth above. 

 

	
	“COMPANY”
	
	XTERA COMMUNICATIONS, INC.
	
	  

	By
	
	  

	Title
	
	“PURCHASER”
	
	  

	Signature
	
	 «Name»

	Printed Name
	
	  

	Soc. Sec. No.
	
	Address:
	
	 «Address»

	
	 «City», «State» «Zip»

  
 -5- 

 EXHIBIT C-2 

ASSIGNMENT SEPARATE FROM CERTIFICATE 

FOR VALUE RECEIVED I, «Name», hereby sell, assign and transfer unto Xtera Communications, Inc.
(                ) shares of the Common Stock of Xtera Communications, Inc. standing in my name of the books of said corporation represented by Certificate
No.      herewith and do hereby irrevocably constitute and appoint
                                         to
transfer the said stock on the books of the within named corporation with full power of substitution in the premises. 
 This Stock
Assignment may be used only in accordance with the Restricted Stock Purchase Agreement between Xtera Communications, Inc. and the undersigned dated             ,
        . 
 Dated:             ,
         
  

			
	Signature:	 	  

 INSTRUCTIONS: Please do not fill in any blanks other than the signature line. The purpose of this assignment is
to enable the Company to exercise its “repurchase option,” as set forth in the Agreement, without requiring additional signatures on the part of the Purchaser. 

 EXHIBIT C-3 

JOINT ESCROW INSTRUCTIONS 

            ,          

Xtera Communications, Inc. 
 500 W. Bethany Drive 

Allen, TX 75013 
 Attention: Corporate Secretary 

Dear                     : 

As Escrow Agent for both Xtera Communications, Inc. (the “Company”), and the undersigned purchaser of stock of the Company (the
“Purchaser”), you are hereby authorized and directed to hold the documents delivered to you pursuant to the terms of that certain Restricted Stock Purchase Agreement (“Agreement”) between the Company and the undersigned, in
accordance with the following instructions: 
 1. In the event the Company and/or any assignee of the Company (referred to collectively for
convenience herein as the “Company”) exercises the Company’s repurchase option set forth in the Agreement, the Company shall give to Purchaser and you a written notice specifying the number of shares of stock to be purchased, the
purchase price, and the time for a closing hereunder at the principal office of the Company. Purchaser and the Company hereby irrevocably authorize and direct you to close the transaction contemplated by such notice in accordance with the terms of
said notice. 
 2. At the closing, you are directed (a) to date the stock assignments necessary for the transfer in question,
(b) to fill in the number of shares being transferred, and (c) to deliver same, together with the certificate evidencing the shares of stock to be transferred, to the Company or its assignee, against the simultaneous delivery to you of the
purchase price (by cash, a check, or some combination thereof) for the number of shares of stock being purchased pursuant to the exercise of the Company’s repurchase option. 

3. Purchaser irrevocably authorizes the Company to deposit with you any certificates evidencing shares of stock to be held by you hereunder
and any additions and substitutions to said shares as defined in the Agreement. Purchaser does hereby irrevocably constitute and appoint you as Purchaser’s attorney-in-fact and agent for the term of this escrow to execute with respect to such
securities all documents necessary or appropriate to make such securities negotiable and to complete any transaction herein contemplated, including but not limited to the filing with any applicable state blue sky authority of any required
applications for consent to, or notice of transfer of, the securities. Subject to the provisions of this paragraph 3, Purchaser shall exercise all rights and privileges of a stockholder of the Company while the stock is held by you. 

4. Upon written request of the Purchaser, but no more than once per calendar year, unless the Company’s repurchase option has been
exercised, you will deliver to Purchaser a certificate or certificates representing so many shares of stock as are not then subject to the Company’s repurchase option. Within 120 days after cessation of Purchaser’s continuous

 
employment by or services to the Company, or any parent or subsidiary of the Company, you will deliver to Purchaser a certificate or certificates representing the aggregate number of shares held
or issued pursuant to the Agreement and not purchased by the Company or its assignees pursuant to exercise of the Company’s repurchase option. 

5. If at the time of termination of this escrow you should have in your possession any documents, securities, or other property belonging to
Purchaser, you shall deliver all of the same to Purchaser and shall be discharged of all further obligations hereunder. 
 6. Your duties
hereunder may be altered, amended, modified or revoked only by a writing signed by all of the parties hereto. 
 7. You shall be obligated
only for the performance of such duties as are specifically set forth herein and may rely and shall be protected in relying or refraining from acting on any instrument reasonably believed by you to be genuine and to have been signed or presented by
the proper party or parties. You shall not be personally liable for any act you may do or omit to do hereunder as Escrow Agent or as attorney-in-fact for Purchaser while acting in good faith, and any act done or omitted by you pursuant to the advice
of your own attorneys shall be conclusive evidence of such good faith. 
 8. You are hereby expressly authorized to disregard any and all
warnings given by any of the parties hereto or by any other person or corporation, excepting only orders or process of courts of law and are hereby expressly authorized to comply with and obey orders, judgments or decrees of any court. In case you
obey or comply with any such order, judgment or decree, you shall not be liable to any of the parties hereto or to any other person, firm or corporation by reason of such compliance, notwithstanding any such order, judgment or decree being
subsequently reversed, modified, annulled, set aside, vacated or found to have been entered without jurisdiction. 
 9. You shall not be
liable in any respect on account of the identity, authorities or rights of the parties executing or delivering or purporting to execute or deliver the Agreement or any documents or papers deposited or called for hereunder. 

10. You shall not be liable for the outlawing of any rights under the Statute of Limitations with respect to these Joint Escrow Instructions
or any documents deposited with you. 
 11. You shall be entitled to employ such legal counsel and other experts as you may deem necessary
properly to advise you in connection with your obligations hereunder, may rely upon the advice of such counsel, and may pay such counsel reasonable compensation therefor. 

12. Your responsibilities as Escrow Agent hereunder shall terminate if you shall cease to be an officer or agent of the Company or if you
shall resign by written notice to each party. In the event of any such termination, the Company shall appoint a successor Escrow Agent 

13. If you reasonably require other or further instruments in connection with these Joint Escrow Instructions or obligations in respect
hereto, the necessary parties hereto shall join in furnishing such instruments. 

  
 -2- 

 14. It is understood and agreed that should any dispute arise with respect to the delivery and/or
ownership or right of possession of the securities held by you hereunder, you are authorized and directed to retain in your possession without liability to anyone all or any part of said securities until such disputes shall have been settled either
by mutual written agreement of the parties concerned or by a final order, decree or judgment of a court of competent jurisdiction after the time for appeal has expired and no appeal has been perfected, but you shall be under no duty whatsoever to
institute or defend any such proceedings. 
 15. Any notice required or permitted hereunder shall be given in writing and shall be deemed
effectively given upon personal delivery or upon deposit in the United States Post Office, by registered or certified mail with postage and fees prepaid, addressed to each of the other parties thereunto entitled at the following addresses or at such
other addresses as a party may designate by ten days’ advance written notice to each of the other parties hereto. 
  

					
	COMPANY:	  	 Xtera Communications, Inc.
 500 W. Bethany
Drive
 Allen, TX 75013
 Attention: Corporate Secretary
	 	
			
	PURCHASER:	  	 «Name»
	 	
			
		  	 «Address»
	 	
			
		  	 «City», «State» «Zip»
	 	
			
	ESCROW AGENT:	  	 Corporate Secretary
 Xtera Communications,
Inc.
 500 W. Bethany Drive
 Allen, TX 75013
	 	

 16. By signing these Joint Escrow Instructions, you become a party hereto only for the purpose of said Joint
Escrow Instructions; you do not become a party to the Agreement. 
 17. This instrument shall be binding upon and inure to the benefit of
the parties hereto, and their respective successors and permitted assigns. 

  
 -3- 

 18. These Joint Escrow Instructions shall be governed by the internal substantive laws, but not
the choice of law rules, of the State of Texas. 
  

	
	XTERA COMMUNICATIONS, INC.
	
	  

	By
	
	  

	Title
	
	“PURCHASER”
	
	  

	Signature
	
	 «Name»

	Typed or Printed Name
	
	ESCROW AGENT
	
	  

	Corporate Secretary

  
 -4- 

 EXHIBIT C-4 

CONSENT OF SPOUSE 
 I,
                                        , spouse
of «Name», have read and approve the foregoing Agreement. In consideration of granting of the right to my spouse to purchase shares of Xtera Communications, Inc., as set forth in the Agreement, I hereby appoint my spouse as my
attorney-in-fact in respect to the exercise of any rights under the Agreement and agree to be bound by the provisions of the Agreement insofar as I may have any rights in said Agreement or any shares issued pursuant thereto under the community
property laws or similar laws relating to marital property in effect in the state of our residence as of the date of the signing of the foregoing Agreement. 
  

							
	Dated:	 	            ,        	 		 	  

		 		 		 	Signature

 EXHIBIT C-5 

ELECTION UNDER SECTION 83(b) 

OF THE INTERNAL REVENUE CODE OF 1986 

The undersigned taxpayer hereby elects, pursuant to Sections 55 and 83(b) of the Internal Revenue Code of 1986, as amended, to include in
taxpayer’s gross income or alternative minimum taxable income, as the case may be, for the current taxable year the amount of any compensation taxable to taxpayer in connection with taxpayer’s receipt of the property described below: 

 

	1.	The name, address, taxpayer identification number and taxable year of the undersigned are as follows: 

  

					
	 	  	 Taxpayer
	  	 Spouse

			
	Name:	  	  
	  	  

		
	Address:	  	  

			
	Social Sec. No.:	  	  
	  	  

			
	Taxable Year:	  	  
	  	  

  

	2.	The property with respect to which the election is made is described as follows:                  shares (the “Shares”) of Common
Stock of Xtera Communications, Inc. (the “Company”). 

  

	3.	The date on which the property was transferred is:             ,         . 

 

	4.	The property is subject to the following restrictions: 

 The Shares may not be transferred and
are subject to forfeiture under the terms of an agreement between the taxpayer and the Company. These restrictions lapse upon the satisfaction of certain conditions contained in such agreement. 

 

	5.	The fair market value at the time of transfer, determined without regard to any restriction other than a restriction which by its terms will never lapse, of such property is:
$        . 

  

	6.	The amount (if any) paid for such property is: $        . 

The undersigned has submitted a copy of this statement to the person for whom the services were performed in connection with the
undersigned’s receipt of the above-described property. The transferee of such property is the person performing the services in connection with the transfer of said property. 

 The undersigned understands that the foregoing election may not be revoked except with the
consent of the Commissioner. 
  

									
	Dated:	 	            ,        	 		 		 	  

		 		 		 		 	Taxpayer

 The undersigned spouse of taxpayer joins in this election. 

 

							
	Dated:	 	            ,        	 		 	  

		 		 		 	Spouse of Taxpayer

  

  
 -2- 

 XTERA COMMUNICATIONS, INC. 

1999 STOCK PLAN 
 STOCK
OPTION AGREEMENT — EARLY EXERCISE 
 Unless otherwise defined herein, the terms defined in the Plan shall have the same defined
meanings in this Option Agreement. 
  

	I.	NOTICE OF STOCK OPTION GRANT 

 «Name» 

«Address» 
 «City», «State»
«Zip» 
 You have been granted an option to purchase Common Stock of the Company, subject to the terms and conditions of the
Plan and this Option Agreement, as follows: 
  

					
	Grant Number	  	 «GrantNo»

		
	Date of Grant	  	 «GrantDate»

		
	Vesting Commencement Date	  	 «VCD»

		
	Exercise Price per Share	  	 $0.08

		
	Total Number of Shares Granted	  	 «Shares»

		
	Total Exercise Price	  	 «Total Price»

			
	Type of Option:	  	  
	  	Incentive Stock Option
			
		  	 X
	  	Nonstatutory Stock Option
		
	Term/Expiration Date:	  	 November 7, 2010

 Exercise and Vesting Schedule: 

So long as Optionee is a Service Provider, this Option shall be exercisable in whole or in part, and shall vest according to the following
vesting schedule: 
 25% of the Shares originally subject to the Option shall vest twelve months after the Vesting Commencement Date, and
1/48 of the Shares originally subject to the Option shall vest each month thereafter, subject to the Optionee’s continuing to be a Service Provider on such dates; provided, however, that in the event that a Change of Control (as
defined below) occurs during the Optionee’s continuing to be a Service Provider, 1/4th of the Shares originally subject to the Option shall become immediately vested and exercisable, and 1/48th of the Shares 

 
originally subject to the Option shall vest each month thereafter, subject to Optionee’s continuing to be a Service Provider on such dates. In addition, in the event that Service
Provider’s employment with the Company is involuntarily terminated by the Company other than for Cause (as defined below) within six (6) months following a Change of Control (as defined below), then all Shares subject to this Option shall
become immediately vested and exercisable. 
 As used herein, “Change of Control” shall mean a merger,
reorganization, sale of substantially all of the assets of the Company or other transaction in which the Company’s stockholders immediately prior to such transaction own immediately after such transaction less than 50% of the equity securities
of the surviving, resulting or acquiring corporation or entity or its parent. 
 As used herein, “Cause”
shall mean (i) Service Provider’s willful misconduct in the execution of Service Provider’s duties which is materially injurious to the Company or its affiliates, (ii) willful and material noncompliance with Company policies or
willful and material breach of any agreement with the Company, (iii) failure or refusal to perform the duties of Service Provider’s position with the Company which is not remedied within thirty days of receipt of notice from the Board
regarding such failure or refusal to perform, or (iv) conviction of, or a plea of nolo contendere with respect to, (a) a felony, or (b) a misdemeanor involving moral turpitude, dishonesty or fraud. 

Termination Period: 

This Option may be exercised, to the extent it is then vested, for three months after Optionee ceases to be a Service Provider. Upon death or
Disability of the Optionee, this Option may be exercised, to the extent it is then vested, for one year after Optionee ceases to be Service Provider. In no event shall this Option be exercised later than the Term/Expiration Date as provided above.

  

	II.	AGREEMENT 

 1. Grant of Option. The Plan Administrator of the Company
hereby grants to the Optionee named in the Notice of Grant (the “Optionee”), an option (the “Option”) to purchase the number of Shares set forth in the Notice of Grant, at the exercise price per Share set forth in the Notice of
Grant (the “Exercise Price”), and subject to the terms and conditions of the Plan, which is incorporated herein by reference. Subject to Section 14(c) of the Plan, in the event of a conflict between the terms and conditions of the
Plan and this Option Agreement, the terms and conditions of the Plan shall prevail. 
 If designated in the Notice of Grant as an Incentive
Stock Option (“ISO”), this Option is intended to qualify as an Incentive Stock Option as defined in Section 422 of the Code. Nevertheless, to the extent that it exceeds the $100,000 rule of Code Section 422(d), this Option shall
be treated as a Nonstatutory Stock Option (“NSO”). 

  
 -2- 

 2. Exercise of Option. This Option shall be exercisable during its term in accordance with
the provisions of Section 9 of the Plan as follows: 
 (a) Right to Exercise. 

(i) Subject to subsections 2(a)(ii) and 2(a)(iii) below, this Option shall be exercisable cumulatively according to the vesting schedule set
forth in the Notice of Grant. Alternatively, at the election of the Optionee, this option may be exercised in whole or in part at any time as to Shares that have not yet vested. For purposes of this Stock Option Agreement, Shares subject to the
Option shall vest based on continued employment of Optionee with the Company. Vested Shares shall not be subject to the Company’s repurchase right (as set forth in the Restricted Stock Purchase Agreement, attached hereto as Exhibit C-1).

 (ii) As a condition to exercising this Option for unvested Shares, the Optionee shall execute the Restricted Stock Purchase Agreement.

 (iii) This Option may not be exercised for a fraction of a Share. 

(b) Method of Exercise. This Option shall be exercisable by delivery of an exercise notice in the form attached as Exhibit A
(the “Exercise Notice”) which shall state the election to exercise the Option, the number of Shares with respect to which the Option is being exercised, and such other representations and agreements as may be required by the Company. The
Exercise Notice shall be accompanied by payment of the aggregate Exercise Price as to all Exercised Shares. This Option shall be deemed to be exercised upon receipt by the Company of such fully executed Exercise Notice accompanied by the aggregate
Exercise Price. 
 No Shares shall be issued pursuant to the exercise of an Option unless such issuance and such exercise complies with
Applicable Laws. Assuming such compliance, for income tax purposes the Shares shall be considered transferred to the Optionee on the date on which the Option is exercised with respect to such Shares. 

3. Optionee’s Representations. In the event the Shares have not been registered under the Securities Act of 1933, as amended, at
the time this Option is exercised, the Optionee shall, if required by the Company, concurrently with the exercise of all or any portion of this Option, deliver to the Company his or her Investment Representation Statement in the form attached hereto
as Exhibit B. 
 4. Lock-Up Period. Optionee hereby agrees that, if so requested by the Company or any representative of the
underwriters (the “Managing Underwriter”) in connection with any registration of the offering of any securities of the Company under the Securities Act, Optionee shall not sell or otherwise transfer any Shares or other securities of the
Company during the 180-day period (or such other period as may be requested in writing by the Managing Underwriter and agreed to in writing by the Company) (the “Market Standoff Period”) following the effective date of a registration
statement of the Company filed under the Securities Act. Such restriction shall apply only to the first registration statement of the Company to become effective under the Securities Act that includes securities to be sold on behalf of the Company
to the public in an underwritten public offering under the Securities Act. The Company may impose stop-transfer instructions with respect to securities subject to the foregoing restrictions until the end of such Market Standoff Period. 

  
 -3- 

 5. Method of Payment. Payment of the aggregate Exercise Price shall be by any of the
following, or a combination thereof, at the election of the Optionee: 
 (a) cash; 

(b) check; 
 (c) consideration
received by the Company under a formal cashless exercise program adopted by the Company in connection with the Plan; or 
 (d) surrender of
other Shares which, (i) in the case of Shares acquired upon exercise of an option, have been owned by the Optionee for more than six (6) months on the date of surrender, and (ii) have a Fair Market Value on the date of surrender equal
to the aggregate Exercise Price of the Exercised Shares. 
 (e) with the Administrator’s consent, delivery of Optionee’s
promissory note (the “Note”) in the form attached hereto as Exhibit E, in the amount of the aggregate Exercise Price of the Exercised Shares together with the execution and delivery by the Optionee of the Security Agreement attached
hereto as Exhibit D. The Note shall bear interest at the “applicable federal rate” prescribed under the Code and its regulations at time of purchase, and shall be secured by a pledge of the Shares purchased by the Note pursuant to
the Security Agreement. 
 6. Restrictions on Exercise. This Option may not be exercised until such time as the Plan has been
approved by the shareholders of the Company, or if the issuance of such Shares upon such exercise or the method of payment of consideration for such shares would constitute a violation of any Applicable Law. 

7. Non-Transferability of Option. This Option may not be transferred in any manner otherwise than by will or by the laws of descent or
distribution and may be exercised during the lifetime of Optionee only by Optionee. The terms of the Plan and this Option Agreement shall be binding upon the executors, administrators, heirs, successors and assigns of the Optionee. 

8. Term of Option. This Option may be exercised only within the term set out in the Notice of Grant, and may be exercised during such
term only in accordance with the Plan and the terms of this Option. 
 9. Tax Consequences. Set forth below is a brief summary as of
the date of this Option of some of the federal tax consequences of exercise of this Option and disposition of the Shares. THIS SUMMARY IS NECESSARILY INCOMPLETE, AND THE TAX LAWS AND REGULATIONS ARE SUBJECT TO CHANGE. THE OPTIONEE SHOULD CONSULT A
TAX ADVISER BEFORE EXERCISING THIS OPTION OR DISPOSING OF THE SHARES. 
 (a) Exercise of ISO. If this Option qualifies as an ISO,
there will be no regular federal income tax liability upon the exercise of the Option, although the excess, if any, of the Fair Market Value of the Shares on the date of exercise over the Exercise Price will be treated as an adjustment to the
alternative minimum tax for federal tax purposes and may subject the Optionee to the alternative minimum tax in the year of exercise. 

  
 -4- 

 (b) Exercise of ISO Following Disability. If the Optionee ceases to be an Employee as a
result of a disability that is not a total and permanent disability as defined in Section 22(e)(3) of the Code, to the extent permitted on the date of termination, the Optionee must exercise an ISO within three months of such termination for
the ISO to be qualified as an ISO. 
 (c) Exercise of Nonstatutory Stock Option. There may be a regular federal income tax liability
upon the exercise of a Nonstatutory Stock Option. The Optionee will be treated as having received compensation income (taxable at ordinary income tax rates) equal to the excess, if any, of the Fair Market Value of the Shares on the date of exercise
over the Exercise Price. If Optionee is an Employee or a former Employee, the Company will be required to withhold from Optionee’s compensation or collect from Optionee and pay to the applicable taxing authorities an amount in cash equal to a
percentage of this compensation income at the time of exercise, and may refuse to honor the exercise and refuse to deliver Shares if such withholding amounts are not delivered at the time of exercise. 

(d) Disposition of Shares. In the case of an NSO, if Shares are held for at least one year, any gain realized on disposition of the
Shares will be treated as long-term capital gain for federal income tax purposes. In the case of an ISO, if Shares transferred pursuant to the Option are held for at least one year after exercise and at least two years after the Date of Grant, any
gain realized on disposition of the Shares will also be treated as long-term capital gain for federal income tax purposes. If Shares purchased under an ISO are disposed of within one year after exercise or two years after the Date of Grant, any gain
realized on such disposition will be treated as compensation income (taxable at ordinary income rates) to the extent of the difference between the Exercise Price and the lesser of (i) the Fair Market Value of the Shares on the date of exercise,
or (ii) the sale price of the Shares. Different rules may apply if the Shares are subject to a substantial risk of forfeiture (within the meaning of Section 83) at the time of purchase. Any additional gain will be taxed as capital gain,
short-term depending on the period that the ISO Shares were held. 
 (e) Notice of Disqualifying Disposition of ISO Shares. If the
Option granted to Optionee herein is an ISO, and if Optionee sells or otherwise disposes of any of the Shares acquired pursuant to the ISO on or before the later of (i) the date two years after the Date of Grant, or (ii) the date one year
after the date of exercise, the Optionee shall immediately notify the Company in writing of such disposition. Optionee agrees that Optionee may be subject to income tax withholding by the Company on the compensation income recognized by the
Optionee. 
 (f) Section 83(b) Election for Unvested Shares Purchased Pursuant to Options. With respect to the exercise of an
Option for unvested Shares, an election may be filed by the Optionee with the Internal Revenue Service, within 30 days of the purchase of the Shares, electing pursuant to Section 83(b) of the Code to be taxed currently on any difference
between the purchase price of the Shares and their Fair Market Value on the date of purchase. In the case of a Nonstatutory Stock Option, this will result in a recognition of taxable income to the Optionee on the date of exercise, measured by the
excess, if any, of the fair market value of the Shares, at the time the Option is exercised over the purchase price for the Shares. Absent such an election, taxable income will be measured and recognized by Optionee at the time or times on

  
 -5- 

 
which the Company’s Repurchase Option lapses. In the case of an Incentive Stock Option, such an election will result in a recognition of income to the Optionee for alternative minimum tax
purposes on the date of exercise, measured by the excess, if any, of the fair market value of the Shares, at the time the option is exercised, over the purchase price for the Shares. Absent such an election, alternative minimum taxable income will
be measured and recognized by Optionee at the time or times on which the Company’s Repurchase Option lapses. Optionee is strongly encouraged to seek the advice of his or her own tax consultants in connection with the purchase of the Shares and
the advisability of filing of the Election under Section 83(b) of the Code. A form of Election under Section 83(b) is attached hereto as Exhibit C-5 for reference. 

OPTIONEE ACKNOWLEDGES THAT IT IS OPTIONEE’S SOLE RESPONSIBILITY AND NOT THE COMPANY’S TO FILE TIMELY THE ELECTION UNDER SECTION
83(b), EVEN IF OPTIONEE REQUESTS THE COMPANY OR ITS REPRESENTATIVE TO MAKE THIS FILING ON OPTIONEE’S BEHALF. 
 10. Entire
Agreement; Governing Law. The Plan is incorporated herein by reference. The Plan and this Option Agreement constitute the entire agreement of the parties with respect to the subject matter hereof and supersede in their entirety all prior
undertakings and agreements of the Company and Optionee with respect to the subject matter hereof, and may not be modified adversely to the Optionee’s interest except by means of a writing signed by the Company and Optionee. This agreement is
governed by the internal substantive laws but not the choice of law rules of Texas. 
 11. No Guarantee of Continued Service.
OPTIONEE ACKNOWLEDGES AND AGREES THAT THE VESTING OF SHARES PURSUANT TO THE VESTING SCHEDULE HEREOF IS EARNED ONLY BY CONTINUING AS A SERVICE PROVIDER AT THE WILL OF THE COMPANY (NOT THROUGH THE ACT OF BEING HIRED, BEING GRANTED THIS OPTION OR
ACQUIRING SHARES HEREUNDER). OPTIONEE FURTHER ACKNOWLEDGES AND AGREES THAT THIS AGREEMENT, THE TRANSACTIONS CONTEMPLATED HEREUNDER AND THE VESTING SCHEDULE SET FORTH HEREIN DO NOT CONSTITUTE AN EXPRESS OR IMPLIED PROMISE OF CONTINUED ENGAGEMENT AS A
SERVICE PROVIDER FOR THE VESTING PERIOD, FOR ANY PERIOD, OR AT ALL, AND SHALL NOT INTERFERE IN ANY WAY WITH OPTIONEE’S RIGHT OR THE COMPANY’S RIGHT TO TERMINATE OPTIONEE’S RELATIONSHIP AS A SERVICE PROVIDER AT ANY TIME, WITH OR
WITHOUT CAUSE. 
 Optionee acknowledges receipt of a copy of the Plan and represents that he or she is familiar with the terms and
provisions thereof, and hereby accepts this Option subject to all of the terms and provisions thereof. Optionee has reviewed the Plan and this Option in their entirety, has had an opportunity to obtain the advice of counsel prior to executing this
Option and fully understands all provisions of the Option. Optionee hereby agrees to accept as binding, conclusive and final all decisions or interpretations of the Administrator upon any questions arising under the Plan or this Option. Optionee
further agrees to notify the Company upon any change in the residence address indicated below. 

  
 -6- 

					
	OPTIONEE:	 		 	XTERA COMMUNICATIONS, INC.
			
	  
	 		 	  

	Signature	 		 	By
			
	 «Name»
	 		 	  

	Print Name	 		 	Title
			
	 «Address»
	 		 	
			
	 «City», «State» «Zip»
	 		 	
	Residence Address	 		 	

  
 -7- 

 EXHIBIT A 

XTERA COMMUNICATIONS, INC. 

1999 STOCK PLAN 

EXERCISE NOTICE 
 Xtera Communications,
Inc. 
 500 W. Bethany Drive 
 Allen, TX 75013 

Attention: Corporate Secretary 
 1. Exercise
of Option. Effective as of today,             ,         , the undersigned (“Optionee”) hereby elects to exercise Optionee’s option
to purchase                  shares of the Common Stock (the “Shares”) of Xtera Communications, Inc. (the “Company”) under and pursuant to the
Company’s 1999 Stock Plan (the “Plan”) and the [    ] Incentive [    ] Nonstatutory Stock Option Agreement dated             ,
         (the “Option Agreement”). 
 2. Delivery of Payment. Purchaser herewith
delivers to the Company the full purchase price of the Shares, as set forth in the Option Agreement. 
 3. Representations of
Optionee. Optionee acknowledges that Optionee has received, read and understood the Plan and the Option Agreement and agrees to abide by and be bound by their terms and conditions. 

4. Rights as Shareholder. Until the issuance of the Shares (as evidenced by the appropriate entry on the books of the Company or of a
duly authorized transfer agent of the Company), no right to vote or receive dividends or any other rights as a shareholder shall exist with respect to the Optioned Stock, notwithstanding the exercise of the Option. The Shares shall be issued to the
Optionee as soon as practicable after the Option is exercised. No adjustment shall be made for a dividend or other right for which the record date is prior to the date of issuance except as provided in Section 12 of the Plan. 

5. Company’s Right of First Refusal. Before any Shares held by Optionee or any transferee (either being sometimes referred to
herein as the “Holder”) may be sold or otherwise transferred (including transfer by gift or operation of law), the Company or its assignee(s) shall have a right of first refusal to purchase the Shares on the terms and conditions set forth
in this Section (the “Right of First Refusal”). 
 (a) Notice of Proposed Transfer. The Holder of the Shares shall deliver
to the Company a written notice (the “Notice”) stating: (i) the Holder’s bona fide intention to sell or otherwise transfer such Shares; (ii) the name of each proposed purchaser or other transferee (“Proposed
Transferee”); (iii) the number of Shares to be transferred to each Proposed Transferee; and (iv) the bona fide cash price or other consideration for which the Holder proposes to transfer the Shares (the “Offered Price”), and
the Holder shall offer the Shares at the Offered Price to the Company or its assignee(s). 

 (b) Exercise of Right of First Refusal. At any time within thirty (30) days after
receipt of the Notice, the Company and/or its assignee(s) may, by giving written notice to the Holder, elect to purchase all, but not less than all, of the Shares proposed to be transferred to any one or more of the Proposed Transferees, at the
purchase price determined in accordance with subsection (c) below. 
 (c) Purchase Price. The purchase price (“Purchase
Price”) for the Shares purchased by the Company or its assignee(s) under this Section shall be the Offered Price. If the Offered Price includes consideration other than cash, the cash equivalent value of the non-cash consideration shall be
determined by the Board of Directors of the Company in good faith. 
 (d) Payment. Payment of the Purchase Price shall be made, at
the option of the Company or its assignee(s), in cash (by check), by cancellation of all or a portion of any outstanding indebtedness of the Holder to the Company (or, in the case of repurchase by an assignee, to the assignee), or by any combination
thereof within 30 days after receipt of the Notice or in the manner and at the times set forth in the Notice. 
 (e) Holder’s Right
to Transfer. If all of the Shares proposed in the Notice to be transferred to a given Proposed Transferee are not purchased by the Company and/or its assignee(s) as provided in this Section, then the Holder may sell or otherwise transfer such
Shares to that Proposed Transferee at the Offered Price or at a higher price, provided that such sale or other transfer is consummated within 120 days after the date of the Notice, that any such sale or other transfer is effected in
accordance with any applicable securities laws and that the Proposed Transferee agrees in writing that the provisions of this Section shall continue to apply to the Shares in the hands of such Proposed Transferee. If the Shares described in the
Notice are not transferred to the Proposed Transferee within such period, a new Notice shall be given to the Company, and the Company and/or its assignees shall again be offered the Right of First Refusal before any Shares held by the Holder may be
sold or otherwise transferred. 
 (f) Exception for Certain Family Transfers. Anything to the contrary contained in this Section
notwithstanding, the transfer of any or all of the Shares during the Optionee’s lifetime or on the Optionee’s death by will or intestacy to the Optionee’s immediate family or a trust for the benefit of the Optionee’s immediate
family shall be exempt from the provisions of this Section. “Immediate Family” as used herein shall mean spouse, lineal descendant or antecedent, father, mother, brother or sister. In such case, the transferee or other recipient shall
receive and hold the Shares so transferred subject to the provisions of this Section, and there shall be no further transfer of such Shares except in accordance with the terms of this Section. 

(g) Termination of Right of First Refusal. The Right of First Refusal shall terminate as to any Shares upon the first sale of Common
Stock of the Company to the general public pursuant to a registration statement filed with and declared effective by the Securities and Exchange Commission under the Securities Act of 1933, as amended. 

6. Tax Consultation. Optionee understands that Optionee may suffer adverse tax consequences as a result of Optionee’s purchase or
disposition of the Shares. Optionee represents that Optionee has consulted with any tax consultants Optionee deems advisable in connection with the purchase or disposition of the Shares and that Optionee is not relying on the Company for any tax
advice. 

  
 -2- 

 7. Restrictive Legends and Stop-Transfer Orders. 

(a) Legends. Optionee understands and agrees that the Company shall cause the legends set forth below or legends substantially
equivalent thereto, to be placed upon any certificate(s) evidencing ownership of the Shares together with any other legends that may be required by the Company or by state or federal securities laws: 

THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 (THE “ACT”) AND MAY NOT BE OFFERED, SOLD
OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL REGISTERED UNDER THE ACT OR, IN THE OPINION OF COMPANY COUNSEL SATISFACTORY TO THE ISSUER OF THESE SECURITIES, SUCH OFFER, SALE OR TRANSFER, PLEDGE OR HYPOTHECATION IS IN COMPLIANCE
THEREWITH. 
 THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN RESTRICTIONS ON TRANSFER AND RIGHT OF FIRST REFUSAL OPTIONS
HELD BY THE ISSUER OR ITS ASSIGNEE(S) AS SET FORTH IN THE EXERCISE NOTICE BETWEEN THE ISSUER AND THE ORIGINAL HOLDER OF THESE SHARES, A COPY OF WHICH MAY BE OBTAINED AT THE PRINCIPAL OFFICE OF THE ISSUER. SUCH TRANSFER RESTRICTIONS AND RIGHT OF
FIRST REFUSAL ARE BINDING ON TRANSFEREES OF THESE SHARES. 
 (b) Stop-Transfer Notices. Optionee agrees that, in order to ensure
compliance with the restrictions referred to herein, the Company may issue appropriate “stop transfer” instructions to its transfer agent, if any, and that, if the Company transfers its own securities, it may make appropriate notations to
the same effect in its own records. 
 (c) Refusal to Transfer. The Company shall not be required (i) to transfer on its books
any Shares that have been sold or otherwise transferred in violation of any of the provisions of this Agreement or (ii) to treat as owner of such Shares or to accord the right to vote or pay dividends to any purchaser or other transferee to
whom such Shares shall have been so transferred. 
 8. Successors and Assigns. The Company may assign any of its rights under this
Agreement to single or multiple assignees, and this Agreement shall inure to the benefit of the successors and assigns of the Company. Subject to the restrictions on transfer herein set forth, this Agreement shall be binding upon Optionee and his or
her heirs, executors, administrators, successors and assigns. 
 9. Interpretation. Any dispute regarding the interpretation of this
Agreement shall be submitted by Optionee or by the Company forthwith to the Administrator which shall review such dispute at its next regular meeting. The resolution of such a dispute by the Administrator shall be final and binding on all parties.

  
 -3- 

 10. Governing Law; Severability. This Agreement is governed by the internal substantive
laws, but not the choice of law rules, of Texas. 
 11. Entire Agreement. The Plan and Option Agreement are incorporated herein by
reference. This Agreement, the Plan, the Restricted Stock Purchase Agreement, the Option Agreement and the Investment Representation Statement constitute the entire agreement of the parties with respect to the subject matter hereof and supersede in
their entirety all prior undertakings and agreements of the Company and Optionee with respect to the subject matter hereof, and may not be modified adversely to the Optionee’s interest except by means of a writing signed by the Company and
Optionee. 
  

					
	Submitted by:	 		 	Accepted by:
			
	OPTIONEE:	 		 	XTERA COMMUNICATIONS, INC.
			
	  
	 		 	  

	Signature	 		 	By
			
	 «Name»
	 		 	  

	Print Name	 		 	Its
			
	Address:	 		 	Address:
			
	 «Address»
	 		 	500 W. Bethany Drive
		 		 	Allen, TX 75013
			
	 «City», «State» «Zip»
	 		 	
		 		 	  

		 		 	Date Received

  
 -4- 

 EXHIBIT B 

INVESTMENT REPRESENTATION STATEMENT 
  

					
	OPTIONEE	 	:	    	
			
	COMPANY	 	:	    	XTERA COMMUNICATIONS, INC.
			
	SECURITY	 	:	    	COMMON STOCK
			
	AMOUNT	 	:	    	
			
	DATE	 	:	    	

 In connection with the purchase of the above-listed Securities, the undersigned Optionee represents to the
Company the following: 
 (a) Optionee is aware of the Company’s business affairs and financial condition and has acquired sufficient
information about the Company to reach an informed and knowledgeable decision to acquire the Securities. Optionee is acquiring these Securities for investment for Optionee’s own account only and not with a view to, or for resale in connection
with, any “distribution” thereof within the meaning of the Securities Act of 1933, as amended (the “Securities Act”). 

(b) Optionee acknowledges and understands that the Securities constitute “restricted securities” under the Securities Act and have
not been registered under the Securities Act in reliance upon a specific exemption therefrom, which exemption depends upon, among other things, the bona fide nature of Optionee’s investment intent as expressed herein. In this connection,
Optionee understands that, in the view of the Securities and Exchange Commission, the statutory basis for such exemption may be unavailable if Optionee’s representation was predicated solely upon a present intention to hold these Securities for
the minimum capital gains period specified under tax statutes, for a deferred sale, for or until an increase or decrease in the market price of the Securities, or for a period of one year or any other fixed period in the future. Optionee further
understands that the Securities must be held indefinitely unless they are subsequently registered under the Securities Act or an exemption from such registration is available. Optionee further acknowledges and understands that the Company is under
no obligation to register the Securities. Optionee understands that the certificate evidencing the Securities will be imprinted with a legend which prohibits the transfer of the Securities unless they are registered or such registration is not
required in the opinion of counsel satisfactory to the Company and any other legend required under applicable state securities laws. 
 (c)
Optionee is familiar with the provisions of Rule 701 and Rule 144, each promulgated under the Securities Act, which, in substance, permit limited public resale of “restricted securities” acquired, directly or indirectly from the issuer
thereof, in a non-public offering subject to the satisfaction of certain conditions. Rule 701 provides that if the issuer qualifies under Rule 701 at the time of the grant of the Option to the Optionee, the exercise will be exempt from registration
under the Securities Act. In the event the Company becomes subject 

 
to the reporting requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, ninety (90) days thereafter (or such longer period as any market stand-off agreement may
require) the Securities exempt under Rule 701 may be resold, subject to the satisfaction of certain of the conditions specified by Rule 144, including: (1) the resale being made through a broker in an unsolicited “broker’s
transaction” or in transactions directly with a market maker (as said term is defined under the Securities Exchange Act of 1934); and, in the case of an affiliate, (2) the availability of certain public information about the Company,
(3) the amount of Securities being sold during any three month period not exceeding the limitations specified in Rule 144(e), and (4) the timely filing of a Form 144, if applicable. 

In the event that the Company does not qualify under Rule 701 at the time of grant of the Option, then the Securities may be resold in certain
limited circumstances subject to the provisions of Rule 144, which requires the resale to occur not less than one year after the later of the date the Securities were sold by the Company or the date the Securities were sold by an affiliate of the
Company, within the meaning of Rule 144; and, in the case of acquisition of the Securities by an affiliate, or by a non-affiliate who subsequently holds the Securities less than two years, the satisfaction of the conditions set forth in sections
(1), (2), (3) and (4) of the paragraph immediately above. 
 (d) Optionee further understands that in the event all of the
applicable requirements of Rule 701 or 144 are not satisfied, registration under the Securities Act, compliance with Regulation A, or some other registration exemption will be required; and that, notwithstanding the fact that Rules 144 and 701 are
not exclusive, the Staff of the Securities and Exchange Commission has expressed its opinion that persons proposing to sell private placement securities other than in a registered offering and otherwise than pursuant to Rules 144 or 701 will have a
substantial burden of proof in establishing that an exemption from registration is available for such offers or sales, and that such persons and their respective brokers who participate in such transactions do so at their own risk. Optionee
understands that no assurances can be given that any such other registration exemption will be available in such event. 
  

	
	Signature of Optionee:
	
	  

 Date:             ,
         

  
 -2- 

 EXHIBIT C-1 

XTERA COMMUNICATIONS, INC. 

1999 STOCK PLAN 

RESTRICTED STOCK PURCHASE AGREEMENT 

THIS AGREEMENT is made between
                                         (the
“Purchaser”) and Xtera Communications, Inc. (the “Company”) as of             ,         . 

RECITALS 
 (1) Pursuant to
the exercise of the stock option (grant number     ) granted to Purchaser under the Company’s 1999 Stock Plan (the “Plan”) and pursuant to the Stock Option Agreement (the “Option Agreement”) dated
                     by and between the Company and Purchaser with respect to such grant, which Plan and Option Agreement are hereby incorporated by
reference, Purchaser has elected to purchase                  of those shares which have not become vested under the vesting schedule set forth in the Option Agreement
(“Unvested Shares”). The Unvested Shares and the shares subject to the Option Agreement which have become vested are sometimes collectively referred to herein as the “Shares”. 

(2) As required by the Option Agreement, as a condition to Purchaser’s election to exercise the option, Purchaser must execute this
Restricted Stock Purchase Agreement, which sets forth the rights and obligations of the parties with respect to Shares acquired upon exercise of the Option. 

1. Repurchase Option. 

(a) If Purchaser’s status as a Service Provider is terminated for any reason, including for cause, death, and disability, the Company
shall have the right and option to purchase from Purchaser, or Purchaser’s personal representative, as the case may be, all of the Purchaser’s Unvested Shares as of the date of such termination at the lesser of the per share price
originally paid by the Purchaser for such Shares or the Fair Market Value (as defined in the Company’s 1999 Stock Plan) per Share as of the date of repurchase, in each case as adjusted for stock splits, stock dividends and similar events having
occurred since the grant date of the Option (the “Repurchase Option”). 
 (b) Upon the occurrence of a termination, the Company
may exercise its Repurchase Option by delivering personally or by registered mail, to Purchaser (or his transferee or legal representative, as the case may be), within ninety (90) days of the termination, a notice in writing indicating the
Company’s intention to exercise the Repurchase Option and setting forth a date for closing not later than thirty (30) days from the mailing of such notice. The closing shall take place at the Company’s office. At the closing, the
holder of the certificates for the Unvested Shares being transferred shall deliver the stock certificate or certificates evidencing the Unvested Shares, and the Company shall deliver the purchase price therefor. 

 (c) At its option, the Company may elect to make payment for the Unvested Shares to a bank
selected by the Company. The Company shall avail itself of this option by a notice in writing to Purchaser stating the name and address of the bank, date of closing, and waiving the closing at the Company’s office. 

(d) If the Company does not elect to exercise the Repurchase Option conferred above by giving the requisite notice within ninety
(90) days following the termination, the Repurchase Option shall terminate. 
 (e) The Repurchase Option shall terminate in accordance
with the Vesting Schedule in Optionee’s Option Agreement. 
 2. Transferability of the Shares; Escrow. 

(a) Purchaser hereby authorizes and directs the secretary of the Company, or such other person designated by the Company, to transfer the
Unvested Shares as to which the Repurchase Option has been exercised from Purchaser to the Company. 
 (b) To insure the availability for
delivery of Purchaser’s Unvested Shares upon repurchase by the Company pursuant to the Repurchase Option under Section 1, Purchaser hereby appoints the secretary, or any other person designated by the Company as escrow agent, as its
attorney-in-fact to sell, assign and transfer unto the Company, such Unvested Shares, if any, repurchased by the Company pursuant to the Repurchase Option and shall, upon execution of this Agreement, deliver and deposit with the secretary of the
Company, or such other person designated by the Company, the share certificates representing the Unvested Shares, together with the stock assignment duly endorsed in blank, attached hereto as Exhibit C-2. The Unvested Shares and stock
assignment shall be held by the secretary in escrow, pursuant to the Joint Escrow Instructions of the Company and Purchaser attached as Exhibit C-3 hereto, until the Company exercises its purchase right as provided in Section 1, until
such Unvested Shares are vested, or until such time as this Agreement no longer is in effect. As a further condition to the Company’s obligations under this Agreement, the spouse of the Purchaser, if any, shall execute and deliver to the
Company the Consent of Spouse attached hereto as Exhibit C-4. Upon vesting of the Unvested Shares, the escrow agent shall promptly deliver to the Purchaser the certificate or certificates representing such Shares in the escrow agent’s
possession belonging to the Purchaser, and the escrow agent shall be discharged of all further obligations hereunder; provided, however, that the escrow agent shall nevertheless retain such certificate or certificates as escrow agent
if so required pursuant to other restrictions imposed pursuant to this Agreement. 
 (c) The Company, or its designee, shall not be liable
for any act it may do or omit to do with respect to holding the Shares in escrow and while acting in good faith and in the exercise of its judgment. 

(d) Transfer or sale of the Shares is subject to restrictions on transfer imposed by any applicable state and federal securities laws. Any
transferee shall hold such Shares subject to all the provisions hereof and the Exercise Notice executed by the Purchaser with respect to any Unvested Shares purchased by Purchaser and shall acknowledge the same by signing a copy of this Agreement.

  
 -2- 

 3. Ownership, Voting Rights, Duties. This Agreement shall not affect in any way the
ownership, voting rights or other rights or duties of Purchaser, except as specifically provided herein. 
 4. Legends. The share
certificate evidencing the Shares issued hereunder shall be endorsed with the following legend (in addition to any legend required under applicable state securities laws): 

THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN RESTRICTIONS UPON TRANSFER AND RIGHTS OF REPURCHASE AS SET FORTH IN AN
AGREEMENT BETWEEN THE COMPANY AND THE STOCKHOLDER, A COPY OF WHICH IS ON FILE WITH THE SECRETARY OF THE COMPANY. 
 5. Adjustment for
Stock Split. All references to the number of Shares and the purchase price of the Shares in this Agreement shall be appropriately adjusted to reflect any stock split, stock dividend or other change in the Shares which may be made by the Company
after the date of this Agreement. 
 6. Notices. Notices required hereunder shall be given in person or by registered mail to the
address of Purchaser shown on the records of the Company, and to the Company at their respective principal executive offices. 
 7.
Survival of Terms. This Agreement shall apply to and bind Purchaser and the Company and their respective permitted assignees and transferees, heirs, legatees, executors, administrators and legal successors. 

8. Section 83(b) Election. Purchaser hereby acknowledges that he or she has been informed that, with respect to the exercise of an
Option for unvested Shares, an election may be filed by the Purchaser with the Internal Revenue Service, within 30 days of the purchase of the Shares, electing pursuant to Section 83(b) of the Code to be taxed currently on any difference
between the purchase price of the Shares and their Fair Market Value on the date of purchase. In the case of a Nonstatutory Stock Option, this will result in a recognition of taxable income to the Purchaser on the date of exercise, measured by the
excess, if any, of the fair market value of the Shares, at the time the Option is exercised over the purchase price for the Shares. Absent such an election, taxable income will be measured and recognized by Purchaser at the time or times on which
the Company’s Repurchase Option lapses. In the case of an Incentive Stock Option, such an election will result in a recognition of income to the Purchaser for alternative minimum tax purposes on the date of exercise, measured by the excess, if
any, of the fair market value of the Shares, at the time the option is exercised, over the purchase price for the Shares. Absent such an election, alternative minimum taxable income will be measured and recognized by Purchaser at the time or times
on which the Company’s Repurchase Option lapses. Purchaser is strongly encouraged to seek the advice of his or her own tax consultants in connection with the purchase of the Shares and the advisability of filing of the Election under
Section 83(b) of the Code. A form of Election under Section 83(b) is attached hereto as Exhibit C-5 for reference. 

  
 -3- 

 PURCHASER ACKNOWLEDGES THAT IT IS PURCHASER’S SOLE RESPONSIBILITY AND NOT THE COMPANY’S
TO FILE TIMELY THE ELECTION UNDER SECTION 83(b), EVEN IF PURCHASER REQUESTS THE COMPANY OR ITS REPRESENTATIVE TO MAKE THIS FILING ON PURCHASER’S BEHALF. 

9. Representations. Purchaser has reviewed with his own tax advisors the federal, state, local and foreign tax consequences of this
investment and the transactions contemplated by this Agreement. Purchaser is relying solely on such advisors and not on any statements or representations of the Company or any of its agents. Purchaser understands that he (and not the Company) shall
be responsible for his own tax liability that may arise as a result of this investment or the transactions contemplated by this Agreement. 

10. Governing Law. This Agreement shall be governed by the internal substantive laws, but not the choice of law rules, of Texas. 

Purchaser represents that he has read this Agreement and is familiar with its terms and provisions. Purchaser hereby agrees to accept as
binding, conclusive and final all decisions or interpretations of the Board upon any questions arising under this Agreement. 

  
 -4- 

 IN WITNESS WHEREOF, this Agreement is deemed made as of the date first set forth above. 

 

	
	“COMPANY”
	
	XTERA COMMUNICATIONS, INC.
	
	  

	By
	
	  

	Title
	
	“PURCHASER”
	
	  

	Signature
	
	  

	Printed Name
	
	  

	Soc. Sec. No.
	
	Address:
	
	  

	
	  

  
 -5- 

 EXHIBIT C-2 

ASSIGNMENT SEPARATE FROM CERTIFICATE 

FOR VALUE RECEIVED I,
                                    , hereby sell, assign and
transfer unto Xtera Communications, Inc. (                ) shares of the Common Stock of Xtera Communications, Inc. standing in my name of the books of said corporation
represented by Certificate No.      herewith and do hereby irrevocably constitute and appoint
                                         to
transfer the said stock on the books of the within named corporation with full power of substitution in the premises. 
 This Stock
Assignment may be used only in accordance with the Restricted Stock Purchase Agreement between Xtera Communications, Inc. and the undersigned dated             ,
        . 
 Dated:             ,
         
  

			
	Signature:	 	  

 INSTRUCTIONS: Please do not fill in any blanks other than the signature line. The purpose of this assignment is
to enable the Company to exercise its “repurchase option,” as set forth in the Agreement, without requiring additional signatures on the part of the Purchaser. 

 EXHIBIT C-3 

JOINT ESCROW INSTRUCTIONS 

            ,          

Xtera Communications, Inc. 
 500 W. Bethany Drive 

Allen, TX 75013 
 Attention: Corporate Secretary 

Dear                     : 

As Escrow Agent for both Xtera Communications, Inc. (the “Company”), and the undersigned purchaser of stock of the Company (the
“Purchaser”), you are hereby authorized and directed to hold the documents delivered to you pursuant to the terms of that certain Restricted Stock Purchase Agreement (“Agreement”) between the Company and the undersigned, in
accordance with the following instructions: 
 1. In the event the Company and/or any assignee of the Company (referred to collectively for
convenience herein as the “Company”) exercises the Company’s repurchase option set forth in the Agreement, the Company shall give to Purchaser and you a written notice specifying the number of shares of stock to be purchased, the
purchase price, and the time for a closing hereunder at the principal office of the Company. Purchaser and the Company hereby irrevocably authorize and direct you to close the transaction contemplated by such notice in accordance with the terms of
said notice. 
 2. At the closing, you are directed (a) to date the stock assignments necessary for the transfer in question,
(b) to fill in the number of shares being transferred, and (c) to deliver same, together with the certificate evidencing the shares of stock to be transferred, to the Company or its assignee, against the simultaneous delivery to you of the
purchase price (by cash, a check, or some combination thereof) for the number of shares of stock being purchased pursuant to the exercise of the Company’s repurchase option. 

3. Purchaser irrevocably authorizes the Company to deposit with you any certificates evidencing shares of stock to be held by you hereunder
and any additions and substitutions to said shares as defined in the Agreement. Purchaser does hereby irrevocably constitute and appoint you as Purchaser’s attorney-in-fact and agent for the term of this escrow to execute with respect to such
securities all documents necessary or appropriate to make such securities negotiable and to complete any transaction herein contemplated, including but not limited to the filing with any applicable state blue sky authority of any required
applications for consent to, or notice of transfer of, the securities. Subject to the provisions of this paragraph 3, Purchaser shall exercise all rights and privileges of a stockholder of the Company while the stock is held by you. 

4. Upon written request of the Purchaser, but no more than once per calendar year, unless the Company’s repurchase option has been
exercised, you will deliver to Purchaser a certificate or certificates representing so many shares of stock as are not then subject to the Company’s repurchase option. Within 120 days after cessation of Purchaser’s continuous

 
employment by or services to the Company, or any parent or subsidiary of the Company, you will deliver to Purchaser a certificate or certificates representing the aggregate number of shares held
or issued pursuant to the Agreement and not purchased by the Company or its assignees pursuant to exercise of the Company’s repurchase option. 

5. If at the time of termination of this escrow you should have in your possession any documents, securities, or other property belonging to
Purchaser, you shall deliver all of the same to Purchaser and shall be discharged of all further obligations hereunder. 
 6. Your duties
hereunder may be altered, amended, modified or revoked only by a writing signed by all of the parties hereto. 
 7. You shall be obligated
only for the performance of such duties as are specifically set forth herein and may rely and shall be protected in relying or refraining from acting on any instrument reasonably believed by you to be genuine and to have been signed or presented by
the proper party or parties. You shall not be personally liable for any act you may do or omit to do hereunder as Escrow Agent or as attorney-in-fact for Purchaser while acting in good faith, and any act done or omitted by you pursuant to the advice
of your own attorneys shall be conclusive evidence of such good faith. 
 8. You are hereby expressly authorized to disregard any and all
warnings given by any of the parties hereto or by any other person or corporation, excepting only orders or process of courts of law and are hereby expressly authorized to comply with and obey orders, judgments or decrees of any court. In case you
obey or comply with any such order, judgment or decree, you shall not be liable to any of the parties hereto or to any other person, firm or corporation by reason of such compliance, notwithstanding any such order, judgment or decree being
subsequently reversed, modified, annulled, set aside, vacated or found to have been entered without jurisdiction. 
 9. You shall not be
liable in any respect on account of the identity, authorities or rights of the parties executing or delivering or purporting to execute or deliver the Agreement or any documents or papers deposited or called for hereunder. 

10. You shall not be liable for the outlawing of any rights under the Statute of Limitations with respect to these Joint Escrow Instructions
or any documents deposited with you. 
 11. You shall be entitled to employ such legal counsel and other experts as you may deem necessary
properly to advise you in connection with your obligations hereunder, may rely upon the advice of such counsel, and may pay such counsel reasonable compensation therefor. 

12. Your responsibilities as Escrow Agent hereunder shall terminate if you shall cease to be an officer or agent of the Company or if you
shall resign by written notice to each party. In the event of any such termination, the Company shall appoint a successor Escrow Agent. 

13. If you reasonably require other or further instruments in connection with these Joint Escrow Instructions or obligations in respect
hereto, the necessary parties hereto shall join in furnishing such instruments. 

  
 -2- 

 14. It is understood and agreed that should any dispute arise with respect to the delivery and/or
ownership or right of possession of the securities held by you hereunder, you are authorized and directed to retain in your possession without liability to anyone all or any part of said securities until such disputes shall have been settled either
by mutual written agreement of the parties concerned or by a final order, decree or judgment of a court of competent jurisdiction after the time for appeal has expired and no appeal has been perfected, but you shall be under no duty whatsoever to
institute or defend any such proceedings. 
 15. Any notice required or permitted hereunder shall be given in writing and shall be deemed
effectively given upon personal delivery or upon deposit in the United States Post Office, by registered or certified mail with postage and fees prepaid, addressed to each of the other parties thereunto entitled at the following addresses or at such
other addresses as a party may designate by ten days’ advance written notice to each of the other parties hereto. 
  

					
	COMPANY:	  	Xtera Communications, Inc.	  	
		  	500 W. Bethany Drive	  	
		  	Allen, TX 75013	  	
		  	Attention: Corporate Secretary	  	
			
	PURCHASER:	  	  
	  	
			
		  	  
	  	
			
		  	  
	  	
			
	ESCROW AGENT:	  	Corporate Secretary	  	
		  	Xtera Communications, Inc.	  	
		  	500 W. Bethany Drive	  	
		  	Allen, TX 75013	  	

 16. By signing these Joint Escrow Instructions, you become a party hereto only for the purpose of said Joint
Escrow Instructions; you do not become a party to the Agreement. 
 17. This instrument shall be binding upon and inure to the benefit of
the parties hereto, and their respective successors and permitted assigns. 

  
 -3- 

 18. These Joint Escrow Instructions shall be governed by the internal substantive laws, but not
the choice of law rules, of the State of Texas. 
  

	
	XTERA COMMUNICATIONS, INC.
	
	  

	By
	
	  

	Title
	
	PURCHASER
	
	  

	Signature
	
	  

	Typed or Printed Name
	
	ESCROW AGENT
	
	  

	Corporate Secretary

  
 -4- 

 EXHIBIT E 

NOTE 
  

			
	$        	 	Dallas, TX
		
	            , 2000	 	

 FOR VALUE RECEIVED,
                                         and his
spouse referred below, if any (collectively, the “Debtor”), promises to pay to Xtera Communications, Inc., a Delaware corporation (the “Company”), or order, the principal sum of
                                        
($        ), together with interest on the unpaid principal hereof from the date hereof at the rate of              percent
(    %) per annum, compounded semiannually. 
 Principal and interest shall be due and payable by Debtor on
            ,         . Payment of principal and interest shall be made in lawful money of the United States of America. 

The undersigned Debtor may at any time prepay all or any portion of the principal or interest owing hereunder. 

This Note is subject to the terms of the Option granted to Debtor by the Company, dated as of
                    . This Note is secured in part by a pledge of the Company’s Common Stock under the terms of a Security Agreement of even
date herewith and is subject to all the provisions thereof. 
 The holder of this Note shall have full recourse against the undersigned
Debtor, and shall not be required to proceed against the collateral securing this Note in the event of default. 
 In the event the
undersigned shall cease to be an employee, director or consultant of the Company for any reason, this Note shall, at the option of the Company, be accelerated, and the whole unpaid balance on this Note of principal and accrued interest shall be
immediately due and payable. 
 Should any action be instituted for the collection of this Note, the reasonable costs and attorneys’
fees therein of the holder shall be paid by the undersigned Debtor. 
  

					
	DEBTOR	 		 	SPOUSE (if applicable)
			
	  
	 		 	  

			
	  
	 		 	  

 AMENDMENT 

TO THE 
 XTERA
COMMUNICATIONS, INC. 
 1999 STOCK PLAN 

This Amendment (the “Amendment”) to the 1999 Stock Plan, as attached hereto as Exhibit A (the
“Plan”), of Xtera Communications, Inc. (the “Company”), is effective as of the 5th day of November, 2009 (the “Effective Date”). Capitalized terms not otherwise defined in this
Amendment shall have the meanings ascribed to them in the Plan. 
 RECITALS 

 

	 	A.	Pursuant to the powers vested in the Board in Section 12 of the Plan, the Company wishes to amend Section 3 therein to reflect certain changes in the maximum number of shares issuable.

  

	 	B.	The Board duly approved and adopted this Amendment on November 4, 2009. 

  

	 	C.	The Stockholders duly approved and adopted this Amendment on November 5, 2009. 

AMENDMENT TO THE PLAN 
 1.
In consideration of the recitals referenced above, the Company hereby adopts the following amendments to the Plan: 
 Upon the Effective
Date, the first paragraph of Section 3 of the Plan is hereby deleted in its entirety and the following is inserted in lieu thereof: 

“Subject to the provisions of Section 12 of the Plan, the maximum aggregate number of Shares which may be subject to option and sold
under the Plan is 24,173,494 Shares. The Shares may be authorized but unissued, or reacquired Common Stock.” 
 IN WITNESS
WHEREOF, the undersigned officer of the Company certifies that the Amendment was duly adopted by the Board on November 4, 2009 and the Stockholders on November 5, 2009. The Company hereby executes the Amendment as of the Effective
Date. 
  

			
	XTERA COMMUNICATIONS, INC.
		
	By:	 	 /s/ Jon R. Hopper

		 	Jon R. Hopper, Chief Executive Officer

 AMENDMENT 

TO THE 
 XTERA
COMMUNICATIONS, INC. 
 1999 STOCK PLAN 

This Amendment (the “Amendment”) to the 1999 Stock Plan, as attached hereto as Exhibit A (the
“Plan”), of Xtera Communications, Inc. (the “Company”), is effective as of the 8th day of December, 2009 (the “Effective Date”). Capitalized terms not otherwise defined in this
Amendment shall have the meanings ascribed to them in the Plan. 
 RECITALS 

 

	 	A.	Pursuant to the powers vested in the Board in Section 14 of the Plan, the Company wishes to amend Section 6 therein to reflect certain changes to the term of the Plan. 

 

	 	B.	The Board duly approved and adopted this Amendment on November 2, 2009. 

  

	 	C.	The Stockholders duly approved and adopted this Amendment on December 8, 2009. 

AMENDMENT TO THE PLAN 
 1.
In consideration of the recitals referenced above, the Company hereby adopts the following amendments to the Plan: 
 Upon the Effective
Date, Section 6 of the Plan is hereby deleted in its entirety and the following is inserted in lieu thereof: 
 “Term of
Plan. The Plan shall become effective upon its adoption by the Board. It shall continue in effect until December 31, 2010 unless sooner terminated under Section 14 of the Plan.” 

IN WITNESS WHEREOF, the undersigned officer of the Company certifies that the Amendment was duly adopted by the Board on
November 2, 2009 and the Stockholders on December 8, 2009. The Company hereby executes the Amendment as of the Effective Date. 
  

			
	XTERA COMMUNICATIONS, INC.
		
	By:	 	 /s/ Jon R. Hopper

		 	Jon R. Hopper, Chief Executive Officer

 AMENDMENT 

TO THE 
 XTERA
COMMUNICATIONS, INC. 
 1999 STOCK PLAN 

This Amendment (the “Amendment”) to the 1999 Stock Plan, as attached hereto as Exhibit A (the
“Plan”), of Xtera Communications, Inc. (the “Company”), is effective as of September 23, 2011 (the “Effective Date”). Capitalized terms not otherwise defined in this
Amendment shall have the meanings ascribed to them in the Plan. 
 RECITALS 

 

	 	A.	Pursuant to the powers vested in the Board in Section 12 of the Plan, the Company wishes to amend Section 3 therein to reflect certain changes in the maximum number of shares issuable.

  

	 	B.	The Board duly approved and adopted this Amendment on September 22, 2011. 

  

	 	C.	The Stockholders duly approved and adopted this Amendment on September 22, 2011. 

AMENDMENT TO THE PLAN 
 1.
In consideration of the recitals referenced above, the Company hereby adopts the following amendments to the Plan: 
 Upon the Effective
Date, the first paragraph of Section 3 of the Plan is hereby deleted in its entirety and the following is inserted in lieu thereof: 

“Subject to the provisions of Section 12 of the Plan, the maximum aggregate number of Shares which may be subject to option and sold
under the Plan is 20,255,406 Shares. The Shares may be authorized but unissued, or reacquired Common Stock. Notwithstanding any other provision in this Plan, on and after September 23, 2011, no further options shall be granted under the terms
of this Plan.” 
 IN WITNESS WHEREOF, the undersigned officer of the Company certifies that the Amendment was duly adopted by
the Board on September 22, 2011 and the Stockholders on September 22, 2011. The Company hereby executes the Amendment as of the Effective Date. 
  

			
	XTERA COMMUNICATIONS, INC.
		
	By:	 	 /s/ Paul J. Colan

		 	Paul J. Colan, Chief Financial OfficerEX-10.3

 Exhibit 10.3 

XTERA COMMUNICATIONS, INC. 

2011 STOCK PLAN 
  

	 	1.	ESTABLISHMENT, PURPOSE AND TERM OF PLAN. 

1.1 Establishment. The Xtera Communications, Inc. 2011 Stock Plan (the “Plan”) is hereby established effective
as of September 22, 2011 (the “Effective Date”). 
 1.2 Purpose. The purpose of the
Plan is to advance the interests of the Participating Company Group and its stockholders by providing an incentive to attract, retain and reward persons performing services for the Participating Company Group and by motivating such persons to
contribute to the growth and profitability of the Participating Company Group. The Company intends that securities issued pursuant to the Plan be exempt from requirements of registration and qualification of such securities pursuant the exemptions
afforded by Rule 701 promulgated under the Securities Act and Section 25102(o) of the of the California Corporations Code or any other applicable exemptions, and the Plan shall be so construed. Further, the Company intends that Awards granted
pursuant to the Plan be exempt from or comply with Section 409A of the Code (including any amendments or replacements of such section), and the Plan shall be so construed. 

1.3 Term of Plan. The Plan shall continue in effect until its termination by the Board; provided, however, that all Awards shall be
granted, if at all, within ten (10) years from the earlier of the date the Plan is adopted by the Board or the date the Plan is duly approved by the stockholders of the Company. 

 

	 	2.	DEFINITIONS AND CONSTRUCTION. 

2.1 Definitions. Whenever used herein, the following terms shall have their respective meanings set forth below: 

(a) “Award” means an Option, Restricted Stock Purchase Right or Restricted Stock Bonus granted under the Plan.

 (b) “Award Agreement” means a written or electronic agreement between the Company and a
Participant setting forth the terms, conditions and restrictions of the Award granted to the Participant. 
 (c)
“Board” means the Board of Directors of the Company. If one or more Committees have been appointed by the Board to administer the Plan, “Board” also means such Committee(s).

 (d) “Cause” means, unless such term or an equivalent term is otherwise defined by the applicable
Award Agreement or other written agreement between a Participant and a Participating Company applicable to an Award, any of the following: (i) the Participant’s theft, dishonesty, willful misconduct, breach of fiduciary duty for personal
profit, or falsification of any Participating Company documents or records; (ii) the Participant’s material failure to abide by a Participating Company’s code of conduct or other policies (including,

 
without limitation, policies relating to confidentiality and reasonable workplace conduct); (iii) the Participant’s unauthorized use, misappropriation, destruction or diversion of any
tangible or intangible asset or corporate opportunity of a Participating Company (including, without limitation, the Participant’s improper use or disclosure of a Participating Company’s confidential or proprietary information);
(iv) any intentional act by the Participant which has a material detrimental effect on a Participating Company’s reputation or business; (v) the Participant’s repeated failure or inability to perform any reasonable assigned
duties after written notice from a Participating Company of, and a reasonable opportunity to cure, such failure or inability; (vi) any material breach by the Participant of any employment or service agreement between the Participant and a
Participating Company, which breach is not cured pursuant to the terms of such agreement; or (vii) the Participant’s conviction (including any plea of guilty or nolo contendere) of any criminal act involving fraud, dishonesty,
misappropriation or moral turpitude, or which impairs the Participant’s ability to perform his or her duties with a Participating Company. 

(e) “Change in Control” means, unless such term or an equivalent term is otherwise defined by the
applicable Award Agreement or other written agreement between the Participant and a Participating Company applicable to an Award, the occurrence of any of the following: 

(i) an Ownership Change Event or a series of related Ownership Change Events (collectively, a
“Transaction”) in which the stockholders of the Company immediately before the Transaction do not retain immediately after the Transaction direct or indirect beneficial ownership of more than fifty percent
(50%) of the total combined voting power of the outstanding securities entitled to vote generally in the election of Directors or, in the case of an Ownership Change Event described in Section 2.1(u)(iii), the entity to which the assets of
the Company were transferred (the “Transferee”), as the case may be; or 
 (ii) approval by the
stockholders of a plan of complete liquidation or dissolution of the Company; 
 provided, however, that a Change in Control shall be deemed not to include
a transaction described in subsections (i) of this Section 2.1(e) in which a majority of the members of the board of directors of the continuing, surviving or successor entity, or parent thereof, immediately after such transaction is
comprised of Incumbent Directors. 
 For purposes of the preceding sentence, indirect beneficial ownership shall include, without limitation, an interest
resulting from ownership of the voting securities of one or more corporations or other business entities which own the Company or the Transferee, as the case may be, either directly or through one or more subsidiary corporations or other business
entities. The Board shall have the right to determine whether multiple sales or exchanges of the voting securities of the Company or multiple Ownership Change Events are related, and its determination shall be final, binding and conclusive. 

(f) “Code” means the Internal Revenue Code of 1986, as amended, and any applicable regulations and
administrative guidelines promulgated thereunder. 

  
 2 

 (g) “Committee” means the compensation committee or other
committee or subcommittee of the Board duly appointed to administer the Plan and having such powers as shall be specified by the Board. Unless the powers of the Committee have been specifically limited, the Committee shall have all of the powers of
the Board granted herein, including, without limitation, the power to amend or terminate the Plan at any time, subject to the terms of the Plan and any applicable limitations imposed by law. 

(h) “Company” means Xtera Communications, Inc., a Delaware corporation, or any successor corporation
thereto. 
 (i) “Consultant” means a person engaged to provide consulting or advisory services (other
than as an Employee or a Director) to a Participating Company, provided that the identity of such person, the nature of such services or the entity to which such services are provided would not preclude the Company from offering or selling
securities to such person pursuant to the Plan in reliance on either the exemption from registration provided by Rule 701 under the Securities Act or any other applicable exemptions or, if the Company is required to file reports pursuant to
Section 13 or 15(d) of the Exchange Act, registration on a Form S-8 Registration Statement under the Securities Act. 
 (j)
“Director” means a member of the Board. 
 (k) “Disability”
means the inability of the Participant, in the opinion of a qualified physician acceptable to the Company, to perform the major duties of the Participant’s position with the Participating Company Group because of the sickness or injury of the
Participant. 
 (l) “Employee” means any person treated as an employee (including an Officer or a
Director who is also treated as an employee) in the records of a Participating Company and, with respect to any Incentive Stock Option granted to such person, who is an employee for purposes of Section 422 of the Code; provided, however, that
neither service as a Director nor payment of a director’s fee shall be sufficient to constitute employment for purposes of the Plan. The Company shall determine in good faith and in the exercise of its discretion whether an individual has
become or has ceased to be an Employee and the effective date of such individual’s employment or termination of employment, as the case may be. For purposes of an individual’s rights, if any, under the terms of the Plan as of the time of
the Company’s determination of whether or not the individual is an Employee, all such determinations by the Company shall be final, binding and conclusive as to such rights, if any, notwithstanding that the Company or any court of law or
governmental agency subsequently makes a contrary determination as to such individual’s status as an Employee. 
 (m)
“Exchange Act” means the Securities Exchange Act of 1934, as amended. 

  
 3 

 (n) “Fair Market Value” means, as of any date, the value
of a share of Stock or other property as determined by the Board, in its discretion, or by the Company, in its discretion, if such determination is expressly allocated to the Company herein, subject to the following: 

(i) If, on such date, the Stock is listed or quoted on a national or regional securities exchange or quotation system, the Fair Market
Value of a share of Stock shall be the closing price of a share of Stock as quoted on the national or regional securities exchange or quotation system constituting the primary market for the Stock, as reported in The Wall Street Journal or
such other source as the Company deems reliable. If the relevant date does not fall on a day on which the Stock has traded on such securities exchange or quotation system, the date on which the Fair Market Value shall be established shall be the
last day on which the Stock was so traded or quoted prior to the relevant date, or such other appropriate day as shall be determined by the Board, in its discretion. 

(ii) If, on such date, the Stock is not listed or quoted on a national or regional securities exchange or quotation system, the Fair Market
Value of a share of Stock shall be as determined by the Board in good faith without regard to any restriction other than a restriction which, by its terms, will never lapse, and in a manner consistent with the requirements of Section 409A of
the Code. 
 (o) “Incentive Stock Option” means an Option intended to be (as set forth in the Award
Agreement) and which qualifies as an incentive stock option within the meaning of Section 422(b) of the Code. 
 (p)
“Incumbent Director” means a director who either (i) is a member of the Board as of the Effective Date or (ii) is elected, or nominated for election, to the Board with the affirmative votes of at least
a majority of the Incumbent Directors at the time of such election or nomination (but excluding a director who was elected or nominated in connection with an actual or threatened proxy contest relating to the election of directors of the Company).

 (q) “Insider” means an Officer, a Director or other person whose transactions in Stock are subject
to Section 16 of the Exchange Act. 
 (r) “Nonstatutory Stock Option” means an Option not
intended to be (as set forth in the Award Agreement) or which does not qualify as an incentive stock option within the meaning of Section 422(b) of the Code. 

(s) “Officer” means any person designated by the Board as an officer of the Company. 

(t) “Option” means an Incentive Stock Option or a Nonstatutory Stock Option granted pursuant to the
Plan. 
 (u) “Ownership Change Event” means the occurrence of any of the following with respect to
the Company: (i) the direct or indirect sale or exchange in a single or series of related transactions by the stockholders of the Company of securities of the Company representing more than fifty percent (50%) of the total combined voting
power of the Company’s then-outstanding securities entitled to vote generally in the election of Directors; (ii) a merger or consolidation in which the Company is a party; or (iii) the sale,
exchange, or transfer of all or substantially all of the assets of the Company (other than a sale, exchange or transfer to one or more subsidiaries of the Company). 

  
 4 

 (v) “Parent Corporation” means any present or future
“parent corporation” of the Company, as defined in Section 424(e) of the Code. 
 (w)
“Participant” means any eligible person who has been granted one or more Awards. 
 (x)
“Participating Company” means the Company or any Parent Corporation or Subsidiary Corporation. 
 (y)
“Participating Company Group” means, at any point in time, all entities collectively which are then Participating Companies. 

(z) “Predecessor Plan” means the Company’s 1999 Stock Plan, as amended. 

(aa) “Restricted Stock Award” means an Award of a Restricted Stock Bonus or a Restricted Stock Purchase
Right. 
 (bb) “Restricted Stock Bonus” means Stock granted to a Participant pursuant to
Section 7. 
 (cc) “Restricted Stock Purchase Right” means a right to purchase Stock granted to
a Participant pursuant to Section 7. 
 (dd) “Rule 16b-3” means
Rule 16b-3 under the Exchange Act, as amended from time to time, or any successor rule or regulation. 

(ee) “Securities Act” means the Securities Act of 1933, as amended. 

(ff) “Service” means a Participant’s employment or service with the Participating Company Group,
whether as an Employee, a Director or a Consultant. Unless otherwise provided by the Board, a Participant’s Service shall not be deemed to have terminated merely because of a change in the capacity in which the Participant renders such Service
or a change in the Participating Company for which the Participant renders such Service, provided that there is no interruption or termination of the Participant’s Service. Furthermore, a Participant’s Service shall not be deemed to have
been interrupted or terminated if the Participant takes any military leave, sick leave, or other bona fide leave of absence approved by the Company. However, unless otherwise provided by the Board, if any such leave taken by a Participant exceeds
ninety (90) days, then on the ninety-first (91st) day following the commencement of such leave the Participant’s Service shall be deemed to have terminated, unless the Participant’s right to return to Service is guaranteed by
statute or contract. Notwithstanding the foregoing, unless otherwise designated by the Company or required by law, an unpaid leave of absence shall not be treated as Service for purposes of determining vesting under the Participant’s Award
Agreement. A Participant’s Service shall be deemed to have terminated either upon an actual termination of Service or upon the business entity for which the Participant performs Service ceasing to be a Participating Company. Subject to the
foregoing, the Company, in its discretion, shall determine whether the Participant’s Service has terminated and the effective date of and reason for such termination. 

  
 5 

 (gg) “Stock” means the common stock of the Company, as
adjusted from time to time in accordance with Section 4.3. 
 (hh) “Subsidiary Corporation”
means any present or future “subsidiary corporation” of the Company, as defined in Section 424(f) of the Code. 
 (ii)
“Ten Percent Stockholder” means a person who, at the time an Award is granted to such person, owns stock possessing more than ten percent (10%) of the total combined voting power of all classes of stock of
a Participating Company within the meaning of Section 422(b)(6) of the Code. 
 (jj) “Trading Compliance
Policy” means the written policy of the Company pertaining to the purchase, sale, transfer or other disposition of the Company’s equity securities by Directors, Officers, Employees or other service providers who may possess
material, nonpublic information regarding the Company or its securities. 
 (kk) “Vesting Conditions”
mean those conditions established in accordance with the Plan prior to the satisfaction of which shares subject to an Award remain subject to forfeiture or a repurchase option in favor of the Company exercisable for the Participant’s monetary
purchase price, if any, for such shares upon the Participant’s termination of Service. 
 2.2 Construction. Captions and titles
contained herein are for convenience only and shall not affect the meaning or interpretation of any provision of the Plan. Except when otherwise indicated by the context, the singular shall include the plural and the plural shall include the
singular. Use of the term “or” is not intended to be exclusive, unless the context clearly requires otherwise. 
  

	 	3.	ADMINISTRATION. 

3.1 Administration by the Board. The Plan shall be administered by the Board. All questions of interpretation of the Plan, of any Award
Agreement or of any other form of agreement or other document employed by the Company in the administration of the Plan or of any Award shall be determined by the Board, and such determinations shall be final, binding and conclusive upon all persons
having an interest in the Plan or such Award, unless fraudulent or made in bad faith. Any and all actions, decisions and determinations taken or made by the Board in the exercise of its discretion pursuant to the Plan or Award Agreement or other
agreement thereunder (other than determining questions of interpretation pursuant to the preceding sentence) shall be final, binding and conclusive upon all persons having an interest therein. All expenses incurred in connection with the
administration of the Plan shall be paid by the Company. 
 3.2 Authority of Officers. Any Officer shall have the authority to act on
behalf of the Company with respect to any matter, right, obligation, determination or election that is the responsibility of or that is allocated to the Company herein, provided the Officer has apparent authority with respect to such matter, right,
obligation, determination or election. 

  
 6 

 3.3 Powers of the Board. In addition to any other powers set forth in the
Plan and subject to the provisions of the Plan, the Board shall have the full and final power and authority, in its discretion: 
 (a) to
determine the persons to whom, and the time or times at which, Awards shall be granted and the number of shares of Stock to be subject to each Award; 

(b) to determine the type of Award granted; 

(c) to determine the Fair Market Value of shares of Stock or other property; 

(d) to determine the terms, conditions and restrictions applicable to each Award (which need not be identical) and any shares acquired
pursuant thereto, including, without limitation, (i) the exercise or purchase price of shares pursuant to any Award, (ii) the method of payment for shares purchased pursuant to any Award, (iii) the method for satisfaction of any tax
withholding obligation arising in connection with any Award, including by the withholding or delivery of shares of Stock, (iv) the timing, terms and conditions of the exercisability or vesting of any Award or any shares acquired pursuant
thereto, (v) the time of expiration of any Award, (vi) the effect of any Participant’s termination of Service on any of the foregoing, and (vii) all other terms, conditions and restrictions applicable to any Award or shares
acquired pursuant thereto not inconsistent with the terms of the Plan; 
 (e) to approve one or more forms of Award Agreement; 

(f) to amend, modify, extend, cancel or renew any Award or to waive any restrictions or conditions applicable to any Award or any shares
acquired pursuant thereto; 
 (g) to reprice or otherwise adjust the exercise price of any Option, or to grant in substitution for any
Option a new Award covering the same or different number of shares of Stock; 
 (h) to accelerate, continue, extend or defer the
exercisability or vesting of any Award or any shares acquired pursuant thereto, including with respect to the period following a Participant’s termination of Service; 

(i) to prescribe, amend or rescind rules, guidelines and policies relating to the Plan, or to adopt sub-plans or supplements to, or
alternative versions of, the Plan, including, without limitation, as the Board deems necessary or desirable to comply with the laws of, or to accommodate the tax policy, accounting principles or custom of, foreign jurisdictions whose citizens may be
granted Awards; and 
 (j) to correct any defect, supply any omission or reconcile any inconsistency in the Plan or any Award Agreement and
to make all other determinations and take such other actions with respect to the Plan or any Award as the Board may deem advisable to the extent not inconsistent with the provisions of the Plan or applicable law. 

  
 7 

 3.4 Administration with Respect to Insiders. With respect to participation by Insiders in
the Plan, at any time that any class of equity security of the Company is registered pursuant to Section 12 of the Exchange Act, the Plan shall be administered in compliance with the requirements, if any, of
Rule 16b-3. 
 3.5 Indemnification. In addition to such other rights of indemnification
as they may have as members of the Board or as officers or employees of the Participating Company Group, to the extent permitted by applicable law, members of the Board and any officers or employees of the Participating Company Group to whom
authority to act for the Board or the Company is delegated shall be indemnified by the Company against all reasonable expenses, including attorneys’ fees, actually and necessarily incurred in connection with the defense of any action, suit or
proceeding, or in connection with any appeal therein, to which they or any of them may be a party by reason of any action taken or failure to act under or in connection with the Plan, or any right granted hereunder, and against all amounts paid by
them in settlement thereof (provided such settlement is approved by independent legal counsel selected by the Company) or paid by them in satisfaction of a judgment in any such action, suit or proceeding, except in relation to matters as to which it
shall be adjudged in such action, suit or proceeding that such person is liable for gross negligence, bad faith or intentional misconduct in duties; provided, however, that within sixty (60) days after the institution of such action, suit or
proceeding, such person shall offer to the Company, in writing, the opportunity at its own expense to handle and defend the same. 
  

	 	4.	SHARES SUBJECT TO PLAN. 

4.1 Maximum Number of Shares Issuable. Subject to adjustment as provided in this Section 4.1 and Sections 4.2 and 4.3, the
maximum aggregate number of shares of Stock that may be issued under the Plan shall be 16,000,000 and shall consist of authorized but unissued or reacquired shares of Stock or any combination thereof. Notwithstanding the foregoing, at any such time
as the offer and sale of securities pursuant to the Plan is subject to compliance with Section 260.140.45 of Title 10 of the California Code of Regulations (“Section 260.140.45”), the total number of shares
of Stock issuable upon the exercise of all outstanding Awards (together with options outstanding under any other stock plan of the Company) and the total number of shares provided for under any stock bonus or similar plan of the Company shall not
exceed thirty percent (30%) (or such other higher percentage limitation as may be approved by the stockholders of the Company pursuant to Section 260.140.45) of the then outstanding shares of the Company as calculated in accordance with
the conditions and exclusions of Section 260.140.45. The maximum aggregate number of shares of Stock that may be issued under this Plan as set forth in this Section 4.1 shall be cumulatively increased from time to time by the number of
shares of Stock subject to that portion of any option outstanding pursuant to the Predecessor Plan as of the Effective Date which, on or after the Effective Date, expires or is terminated or canceled for any reason without having been exercised in
full; provided, however, that the aggregate number of shares of Stock authorized for issuance under the Predecessor Plan that may become authorized for issuance under this Plan pursuant to this Section 4.1 shall not exceed 10,000,000. 

  
 8 

 4.2 Share Counting. If an outstanding Award for any reason expires or is terminated or
canceled without having been exercised or settled in full, or if shares of Stock are acquired pursuant to an Award subject to forfeiture or repurchase and are forfeited or repurchased by the Company for an amount not greater than the
Participant’s exercise or purchase price, the shares of Stock allocable to the terminated portion of such Award or such forfeited or repurchased shares of Stock shall again be available for issuance under the Plan. Shares of Stock shall not be
deemed to have been issued pursuant to the Plan (a) with respect to any portion of an Award that is settled in cash or (b) to the extent such shares are withheld or reacquired by the Company in satisfaction of tax withholding obligations
pursuant to Section 10.2. If the exercise price of an Option is paid by tender to the Company, or attestation to the ownership, of shares of Stock owned by the Participant, or by means of a Net Exercise, the number of shares available for
issuance under the Plan shall be reduced by the net number of shares issued upon the exercise of the Option. 
 4.3 Adjustments for
Changes in Capital Structure. Subject to any required action by the stockholders of the Company and the requirements of Sections 409A and 424 of the Code to the extent applicable, in the event of any change in the Stock effected
without receipt of consideration by the Company, whether through merger, consolidation, reorganization, reincorporation, recapitalization, reclassification, stock dividend, stock split, reverse stock split, split-up, split-off, spin-off, combination
of shares, exchange of shares, or similar change in the capital structure of the Company, or in the event of payment of a dividend or distribution to the stockholders of the Company in a form other than Stock (excepting regular, periodic cash
dividends) that has a material effect on the Fair Market Value of shares of Stock, appropriate and proportionate adjustments shall be made in the number and kind of shares subject to the Plan and to any outstanding Awards, in the ISO Share Limit set
forth in Section 5.3(a), and in the exercise or purchase price per share under any outstanding Awards in order to prevent dilution or enlargement of Participants’ rights under the Plan. For purposes of the foregoing, conversion of any
convertible securities of the Company shall not be treated as “effected without receipt of consideration by the Company.” If a majority of the shares which are of the same class as the shares that are subject to outstanding Awards are
exchanged for, converted into, or otherwise become (whether or not pursuant to an Ownership Change Event) shares of another corporation (the “New Shares”), the Board may unilaterally amend the outstanding Awards
to provide that such Awards are for New Shares. In the event of any such amendment, the number of shares subject to, and the exercise or purchase price per share of, the outstanding Awards shall be adjusted in a fair and equitable manner as
determined by the Board, in its discretion. Any fractional share resulting from an adjustment pursuant to this Section shall be rounded down to the nearest whole number, and the exercise or purchase price per share shall be rounded up to the nearest
whole cent. In no event may the exercise or purchase price, if any, under any Award be decreased to an amount less than the par value, if any, of the stock subject to the Award. Such adjustments shall be determined by the Board, and its
determination shall be final, binding and conclusive. 
 4.4 Assumption or Substitution of Awards. The Board may, without affecting
the number of shares of Stock available pursuant to Section 4.1, authorize the issuance or assumption of benefits under this Plan in connection with any merger, consolidation, acquisition of property or stock, or reorganization upon such terms
and conditions as it may deem appropriate, subject to compliance with Section 409A and any other applicable provisions of the Code. 

  
 9 

	 	5.	ELIGIBILITY, PARTICIPATION AND OPTION LIMITATIONS. 

5.1 Persons Eligible for Awards. Awards may be granted only to Employees, Consultants and Directors. 

5.2 Participation in the Plan. Awards are granted solely at the discretion of the Board. Eligible persons may be granted more than one
Award. However, eligibility in accordance with this Section shall not entitle any person to be granted an Award, or, having been granted an Award, to be granted an additional Award. 

5.3 Incentive Stock Option Limitations. 

(a) Maximum Number of Shares Issuable Pursuant to Incentive Stock Options. Subject to Section 4.1 and adjustment as provided in
Sections 4.2 and 4.3, the maximum aggregate number of shares of Stock that may be issued under the Plan pursuant to the exercise of Incentive Stock Options shall not exceed 16,000,000 shares (the “ISO Share
Limit”). The maximum aggregate number of shares of Stock that may be issued under the Plan pursuant to all Awards other than Incentive Stock Options shall be the number of shares determined in accordance with Section 4.1,
subject to adjustment as provided in Sections 4.2 and 4.3. 
 (b) Persons Eligible. An Incentive Stock Option may be granted
only to a person who, on the effective date of grant, is an Employee. Any person who is not an Employee on the effective date of the grant of an Option to such person may be granted only a Nonstatutory Stock Option. 

(c) Fair Market Value Limitation. To the extent that options designated as Incentive Stock Options (granted under all
stock plans of the Participating Company Group, including the Plan) become exercisable by a Participant for the first time during any calendar year for stock having a Fair Market Value greater than One Hundred Thousand Dollars ($100,000), the
portions of such options which exceed such amount shall be treated as Nonstatutory Stock Options. For purposes of this Section, options designated as Incentive Stock Options shall be taken into account in the order in which they were granted, and
the Fair Market Value of stock shall be determined as of the time the option with respect to such stock is granted. If the Code is amended to provide for a limitation different from that set forth in this Section, such different limitation shall be
deemed incorporated herein effective as of the date and with respect to such Options as required or permitted by such amendment to the Code. If an Option is treated as an Incentive Stock Option in part and as a Nonstatutory Stock Option in part by
reason of the limitation set forth in this Section, the Participant may designate which portion of such Option the Participant is exercising. In the absence of such designation, the Participant shall be deemed to have exercised the Incentive Stock
Option portion of the Option first. Upon exercise of the Option, Shares issued pursuant to each such portion shall be separately identified. 

  
 10 

	 	6.	STOCK OPTIONS. 

 Options shall be
evidenced by Award Agreements specifying the number of shares of Stock covered thereby, in such form as the Board shall from time to time establish. Such Award Agreements may incorporate all or any of the terms of the Plan by reference and shall
comply with and be subject to the following terms and conditions: 
 6.1 Exercise Price. The exercise price for each
Option shall be established in the discretion of the Board; provided, however, that (a) the exercise price per share for an Option shall be not less than the Fair Market Value of a share of Stock on the effective date of grant of the Option and
(b) no Incentive Stock Option granted to a Ten Percent Stockholder shall have an exercise price per share less than one hundred ten percent (110%) of the Fair Market Value of a share of Stock on the effective date of grant of the Option.
Notwithstanding the foregoing, an Option (whether an Incentive Stock Option or a Nonstatutory Stock Option) may be granted with an exercise price lower than the minimum exercise price set forth above if such Option is granted pursuant to an
assumption or substitution for another option in a manner that would qualify under the provisions of Section 409A or Section 424(a) of the Code, as applicable. 

6.2 Exercisability and Term of Options. Options shall be exercisable at such time or times, or upon such event or events,
and subject to such terms, conditions, performance criteria and restrictions as shall be determined by the Board and set forth in the Award Agreement evidencing such Option; provided, however, that (a) no Option shall be exercisable after the
expiration of ten (10) years after the effective date of grant of such Option, (b) no Incentive Stock Option granted to a Ten Percent Stockholder shall be exercisable after the expiration of five (5) years after the effective date of
grant of such Option, and (c) no Option granted to an Employee who is a non-exempt employee for purposes of the Fair Labor Standards Act of 1938, as amended, shall be first exercisable until at least six (6) months following the date of
grant of such Option (except in the event of such Employee’s death, disability or retirement, upon a Change in Control, or as otherwise permitted by the Worker Economic Opportunity Act). Subject to the foregoing, unless otherwise specified by
the Board in the grant of an Option, each Option shall terminate ten (10) years after the effective date of grant of the Option, unless earlier terminated in accordance with its provisions. 

6.3 Payment of Exercise Price. 

(a) Forms of Consideration Authorized. Except as otherwise provided below, payment of the exercise price for the number of
shares of Stock being purchased pursuant to any Option shall be made (i) in cash, by check or in cash equivalent, (ii) if permitted by the Company and subject to the limitations contained in Section 6.3(b), by means of (1) a
Stock Tender Exercise, (2) a Cashless Exercise or (3) a Net Exercise; (iii) by such other consideration as may be approved by the Board from time to time to the extent permitted by applicable law, or (iv) by any combination
thereof. The Board may at any time or from time to time grant Options which do not permit all of the foregoing forms of consideration to be used in payment of the exercise price or which otherwise restrict one or more forms of consideration. 

  
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 (b) Limitations on Forms of Consideration. 

(i) Stock Tender Exercise. A “Stock Tender Exercise” means the delivery of a properly executed
exercise notice accompanied by a Participant’s tender to the Company, or attestation to the ownership, in a form acceptable to the Company of whole shares of Stock having a Fair Market Value that does not exceed the aggregate exercise price for
the shares with respect to which the Option is exercised. A Stock Tender Exercise shall not be permitted if it would constitute a violation of the provisions of any law, regulation or agreement restricting the redemption of the Company’s stock.
If required by the Company, the Option may not be exercised by tender to the Company, or attestation to the ownership, of shares of Stock unless such shares either have been owned by the Participant for a period of time required by the Company (and
not used for another option exercise by attestation during such period) or were not acquired, directly or indirectly, from the Company. 

(ii) Cashless Exercise. A Cashless Exercise shall be permitted only upon the class of shares subject to the Option becoming publicly
traded in an established securities market. A “Cashless Exercise” means the delivery of a properly executed exercise notice together with irrevocable instructions to a broker providing for the assignment to the
Company of the proceeds of a sale or loan with respect to some or all of the shares being acquired upon the exercise of the Option (including, without limitation, through an exercise complying with the provisions of Regulation T as promulgated
from time to time by the Board of Governors of the Federal Reserve System). The Company reserves, at any and all times, the right, in the Company’s sole and absolute discretion, to establish, decline to approve or terminate any program or
procedures for the exercise of Options by means of a Cashless Exercise, including with respect to one or more Participants specified by the Company notwithstanding that such program or procedures may be available to other Participants. 

(iii) Net Exercise. A “Net Exercise” means the delivery of a properly executed exercise notice
followed by a procedure pursuant to which (1) the Company will reduce the number of shares otherwise issuable to a Participant upon the exercise of an Option by the largest whole number of shares having a Fair Market Value that does not exceed
the aggregate exercise price for the shares with respect to which the Option is exercised, and (2) the Participant shall pay to the Company in cash the remaining balance of such aggregate exercise price not satisfied by such reduction in the
number of whole shares to be issued. 
 6.4 Effect of Termination of Service. 

(a) Option Exercisability. Subject to earlier termination of the Option as otherwise provided by this Plan and unless a
longer exercise period is provided by the Board, an Option shall terminate immediately upon the Participant’s termination of Service to the extent that it is then unvested and shall be exercisable after the Participant’s termination of
Service to the extent it is then vested only during the applicable time period determined in accordance with this Section and thereafter shall terminate: 

(i) Disability. If the Participant’s Service terminates because of the Disability of the Participant, the Option, to the extent
unexercised and exercisable for vested shares on the date on which the Participant’s Service terminated, may be exercised by the 

  
 12 

 
Participant (or the Participant’s guardian or legal representative) at any time prior to the expiration of twelve (12) months after the date on which the Participant’s Service
terminated, but in any event no later than the date of expiration of the Option’s term as set forth in the Award Agreement evidencing such Option (the “Option Expiration Date”). 

(ii) Death. If the Participant’s Service terminates because of the death of the Participant, the Option, to the extent
unexercised and exercisable for vested shares on the date on which the Participant’s Service terminated, may be exercised by the Participant’s legal representative or other person who acquired the right to exercise the Option by reason of
the Participant’s death at any time prior to the expiration of twelve (12) months after the date on which the Participant’s Service terminated, but in any event no later than the Option Expiration Date. The Participant’s Service
shall be deemed to have terminated on account of death if the Participant dies within three (3) months after the Participant’s termination of Service. 

(iii) Termination for Cause. Notwithstanding any other provision of the Plan to the contrary, if the Participant’s Service is
terminated for Cause, the Option shall terminate in its entirety and cease to be exercisable immediately upon such termination of Service. 

(iv) Other Termination of Service. If the Participant’s Service terminates for any reason, except Disability, death or Cause, the
Option, to the extent unexercised and exercisable for vested shares on the date on which the Participant’s Service terminated, may be exercised by the Participant at any time prior to the earlier of (A) the expiration of three
(3) months after the date on which the Participant’s Service terminated or (B) the Option Expiration Date. 
 (b)
Extension if Exercise Prevented by Law. Notwithstanding the foregoing other than termination of Service for Cause, if the exercise of an Option within the applicable time periods set forth in Section 6.4(a) is prevented by
the provisions of Section 11 below, the Option shall remain exercisable until the later of (i) thirty (30) days after the date such exercise first would no longer be prevented by such provisions or (ii) the end of the applicable
time period under Section 6.4(a), but in any event no later than the Option Expiration Date. 
 6.5 Transferability of Options.
During the lifetime of the Participant, an Option shall be exercisable only by the Participant or the Participant’s guardian or legal representative. An Option shall not be subject in any manner to anticipation, alienation, sale, exchange,
transfer, assignment, pledge, encumbrance, or garnishment by creditors of the Participant or the Participant’s beneficiary, except transfer by will or by the laws of descent and distribution. Notwithstanding the foregoing, to the extent
permitted by the Board, in its discretion, and set forth in the Award Agreement evidencing such Option, an Option shall be assignable or transferable subject to the applicable limitations, if any, described in Rule 701 under the Securities Act and
the General Instructions to Form S-8 Registration Statement under the Securities Act or, in the case of an Incentive Stock Option, only as permitted by applicable regulations under Section 421 of the Code in a manner that does not disqualify
such Option as an Incentive Stock Option. 

  
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	 	7.	RESTRICTED STOCK AWARDS. 

Restricted Stock Awards shall be evidenced by Award Agreements specifying whether the Award is a Restricted Stock Bonus or a Restricted Stock
Purchase Right and the number of shares of Stock subject to the Award, in such form as the Board shall from time to time establish. Such Award Agreements may incorporate all or any of the terms of the Plan by reference and shall comply with and be
subject to the following terms and conditions: 
 7.1 Types of Restricted Stock Awards Authorized. Restricted Stock Awards may be
granted in the form of either a Restricted Stock Bonus or a Restricted Stock Purchase Right. Restricted Stock Awards may be granted upon such conditions as the Board shall determine, including, without limitation, upon the attainment of one or more
performance goals. 
 7.2 Purchase Price. The purchase price for shares of Stock issuable under each Restricted Stock Purchase
Right shall be established by the Board in its discretion. No monetary payment (other than applicable tax withholding) shall be required as a condition of receiving shares of Stock pursuant to a Restricted Stock Bonus, the consideration for which
shall be services actually rendered to a Participating Company or for its benefit. Notwithstanding the foregoing, if required by applicable state corporate law, the Participant shall furnish consideration in the form of cash or past services
rendered to a Participating Company or for its benefit having a value not less than the par value of the shares of Stock subject to a Restricted Stock Award. 

7.3 Purchase Period. A Restricted Stock Purchase Right shall be exercisable within a period established by the Board, which
shall in no event exceed thirty (30) days from the effective date of the grant of the Restricted Stock Purchase Right. 
 7.4
Payment of Purchase Price. Except as otherwise provided below, payment of the purchase price for the number of shares of Stock being purchased pursuant to any Restricted Stock Purchase Right shall be made (a) in cash, by check or in cash
equivalent, (b) by such other consideration as may be approved by the Board from time to time to the extent permitted by applicable law, or (c) by any combination thereof. 

7.5 Vesting and Restrictions on Transfer. Shares issued pursuant to any Restricted Stock Award may (but need not) be made
subject to Vesting Conditions based upon the satisfaction of such Service requirements, conditions, restrictions or performance criteria, as shall be established by the Board and set forth in the Award Agreement evidencing such Award. During any
period in which shares acquired pursuant to a Restricted Stock Award remain subject to Vesting Conditions, such shares may not be sold, exchanged, transferred, pledged, assigned or otherwise disposed of other than pursuant to an Ownership Change
Event or as provided in Section 7.8. The Board, in its discretion, may provide in any Award Agreement evidencing a Restricted Stock Award that, if the satisfaction of Vesting Conditions with respect to any shares subject to such Restricted
Stock Award would otherwise occur on a day on which the sale of such shares would violate the provisions of the Trading Compliance Policy, then satisfaction of the Vesting Conditions automatically shall be determined on the next trading day on which
the sale of such shares would not violate the Trading Compliance Policy. Upon request by the 

  
 14 

 
Company, each Participant shall execute any agreement evidencing such transfer restrictions prior to the receipt of shares of Stock hereunder and shall promptly present to the Company any and all
certificates representing shares of Stock acquired hereunder for the placement on such certificates of appropriate legends evidencing any such transfer restrictions. 

7.6 Voting Rights; Dividends and Distributions. Except as provided in this Section, Section 7.5 and any Award Agreement, during
any period in which shares acquired pursuant to a Restricted Stock Award remain subject to Vesting Conditions, the Participant shall have all of the rights of a stockholder of the Company holding shares of Stock, including the right to vote such
shares and to receive all dividends and other distributions paid with respect to such shares; provided, however, that if so determined by the Board and provided by the Award Agreement, such dividends and distributions shall be subject to the same
Vesting Conditions as the shares subject to the Restricted Stock Award with respect to which such dividends or distributions were paid, and otherwise shall be paid no later than the end of the calendar year in which such dividends or distributions
are paid to stockholders (or, if later, the 15th day of the third month following the date such dividends or distributions are paid to stockholders). In the event of a dividend or distribution paid in shares of Stock or other property or any other
adjustment made upon a change in the capital structure of the Company as described in Section 4.3, any and all new, substituted or additional securities or other property (other than regular, periodic cash dividends) to which the Participant is
entitled by reason of the Participant’s Restricted Stock Award shall be immediately subject to the same Vesting Conditions as the shares subject to the Restricted Stock Award with respect to which such dividends or distributions were paid or
adjustments were made. 
 7.7 Effect of Termination of Service. Unless otherwise provided by the Board in the Award Agreement
evidencing a Restricted Stock Award, if a Participant’s Service terminates for any reason, whether voluntary or involuntary (including the Participant’s death or disability), then (a) the Company shall have the option to repurchase
for the purchase price paid by the Participant any shares acquired by the Participant pursuant to a Restricted Stock Purchase Right which remain subject to Vesting Conditions as of the date of the Participant’s termination of Service and
(b) the Participant shall forfeit to the Company any shares acquired by the Participant pursuant to a Restricted Stock Bonus which remain subject to Vesting Conditions as of the date of the Participant’s termination of Service. The Company
shall have the right to assign at any time any repurchase right it may have, whether or not such right is then exercisable, to one or more persons as may be selected by the Company. 

7.8 Nontransferability of Restricted Stock Award Rights. Rights to acquire shares of Stock pursuant to a Restricted Stock Award
shall not be subject in any manner to anticipation, alienation, sale, exchange, transfer, assignment, pledge, encumbrance or garnishment by creditors of the Participant or the Participant’s beneficiary, except transfer by will or the laws of
descent and distribution. All rights with respect to a Restricted Stock Award granted to a Participant hereunder shall be exercisable during his or her lifetime only by such Participant or the Participant’s guardian or legal representative.

  
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	 	8.	STANDARD FORMS OF AWARD AGREEMENTS. 

8.1 Award Agreements. Each Award shall comply with and be subject to the terms and conditions set forth in the appropriate
form of Award Agreement approved by the Board and as amended from time to time. No Award or purported Award shall be a valid and binding obligation of the Company unless evidenced by a fully executed Award Agreement, which execution may be evidenced
by electronic means. 
 8.2 Authority to Vary Terms. The Board shall have the authority from time to time to vary the
terms of any standard form of Award Agreement either in connection with the grant or amendment of an individual Award or in connection with the authorization of a new standard form or forms; provided, however, that the terms and conditions of any
such new, revised or amended standard form or forms of Award Agreement are not inconsistent with the terms of the Plan. 
  

	 	9.	CHANGE IN CONTROL. 

9.1 Effect of Change in Control on Awards. Subject to the requirements and limitations of Section 409A of the Code,
if applicable, the Board may provide for any one or more of the following: 
 (a) Accelerated Vesting. In its discretion, the
Board may provide in the grant of any Award or at any other time may take such action as it deems appropriate to provide for acceleration of the exercisability and/or vesting in connection with a Change in Control of each or any outstanding Award or
portion thereof and shares acquired pursuant thereto upon such conditions, including termination of the Participant’s Service prior to, upon, or following such Change in Control, and to such extent as the Board shall determine. 

(b) Assumption, Continuation or Substitution of Awards. In the event of a Change in Control, the surviving, continuing,
successor, or purchasing corporation or other business entity or parent thereof, as the case may be (the “Acquiror”), may, without the consent of any Participant, assume or continue the Company’s rights and
obligations under each or any Award or portion thereof outstanding immediately prior to the Change in Control or substitute for each or any such outstanding Award or portion thereof a substantially equivalent award with respect to the
Acquiror’s stock. For purposes of this Section, if so determined by the Board, in its discretion, an Award or any portion thereof shall be deemed assumed if, following the Change in Control, the Award confers the right to receive, subject to
the terms and conditions of the Plan and the applicable Award Agreement, for each share of Stock subject to such portion of the Award immediately prior to the Change in Control, the consideration (whether stock, cash, other securities or property or
a combination thereof) to which a holder of a share of Stock on the effective date of the Change in Control was entitled (and if holders were offered a choice of consideration, the type of consideration chosen by the holders of a majority of the
outstanding shares of Stock); provided, however, that if such consideration is not solely common stock of the Acquiror, the Board may, with the consent of the Acquiror, provide for the consideration to be received upon the exercise of the Award for
each share of Stock to consist solely of common stock of the Acquiror equal in Fair Market Value to the per share consideration received by holders of Stock pursuant to the Change in Control. If any portion of such consideration may be

  
 16 

 
received by holders of Stock pursuant to the Change in Control on a contingent or delayed basis, the Board may, in its discretion, determine such Fair Market Value per share as of the time of the
Change in Control on the basis of the Board’s good faith estimate of the present value of the probable future payment of such consideration. Any Award or portion thereof which is neither assumed or continued by the Acquiror in connection with
the Change in Control nor exercised as of the time of consummation of the Change in Control shall terminate and cease to be outstanding effective as of the time of consummation of the Change in Control. Notwithstanding the foregoing, shares acquired
upon exercise of an Award prior to the Change in Control and any consideration received pursuant to the Change in Control with respect to such shares shall continue to be subject to all applicable provisions of the Award Agreement evidencing such
Award except as otherwise provided in such Award Agreement. 
 (c) Cash-Out of Outstanding Awards. The Board may, in its
discretion and without the consent of any Participant, determine that, upon the occurrence of a Change in Control, each or any Award or portion thereof outstanding immediately prior to the Change in Control and not previously exercised or settled
shall be canceled in exchange for a payment with respect to each vested share (and each unvested share, if so determined by the Board) of Stock subject to such canceled Award in (i) cash, (ii) stock of the Company or of a corporation or
other business entity a party to the Change in Control, or (iii) other property which, in any such case, shall be in an amount having a Fair Market Value equal to the Fair Market Value of the consideration to be paid per share of Stock in the
Change in Control, reduced (but not below zero) by the exercise or purchase price per share, if any, under such Award. If any portion of such consideration may be received by holders of Stock pursuant to the Change in Control on a contingent or
delayed basis, the Board may, in its sole discretion, determine such Fair Market Value per share as of the time of the Change in Control on the basis of the Board’s good faith estimate of the present value of the probable amount of future
payment of such consideration. In the event such determination is made by the Board, an Award having an exercise or purchase price per share equal to or greater than the Fair Market Value of the consideration to be paid per share of Stock in the
Change in Control may be canceled without payment of consideration to the holder thereof. Payment pursuant to this Section (reduced by applicable withholding taxes, if any) shall be made to Participants in respect of the vested portions of their
canceled Awards as soon as practicable following the date of the Change in Control and in respect of the unvested portions of their canceled Awards in accordance with the vesting schedules applicable to such Awards. 

9.2 Federal Excise Tax Under Section 4999 of the Code. 

(a) Excess Parachute Payment. If any acceleration of vesting pursuant to an Award and any other payment or benefit received or
to be received by a Participant would subject the Participant to any excise tax pursuant to Section 4999 of the Code due to the characterization of such acceleration of vesting, payment or benefit as an “excess parachute payment”
under Section 280G of the Code, then, provided such election would not subject the Participant to taxation under Section 409A of the Code, the Participant may elect, in his or her sole discretion, to reduce the amount of any acceleration
of vesting called for under the Award in order to avoid such characterization. 
 (b) Determination by Independent
Accountants. To aid the Participant in making any election called for under Section 9.2(a), no later than the date of the occurrence of any event that might reasonably be anticipated to result in an “excess parachute
payment” to the Participant as described in Section 9.2(a), the Company shall request a determination in writing by independent public accountants selected by the Company (the
“Accountants”). As soon as practicable thereafter, the Accountants shall determine and report to the Company and the Participant the amount of such acceleration of vesting, payments and benefits which would
produce the greatest after-tax benefit to the Participant. For the purposes of such determination, the Accountants may rely on reasonable, good faith interpretations concerning the application of Sections 280G and 4999 of the Code. The Company and
the Participant shall furnish to the Accountants such information and documents as the Accountants may reasonably request in order to make their required determination. The Company shall bear all fees and expenses the Accountants charge in
connection with their services contemplated by this Section 9. 

  
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	 	10.	TAX WITHHOLDING. 

10.1 Tax Withholding in General. The Company shall have the right to deduct from any and all payments made under the Plan, or to require
the Participant, through payroll withholding, cash payment or otherwise, to make adequate provision for, the federal, state, local and foreign taxes (including any social insurance), if any, required by law to be withheld by any Participating
Company with respect to an Award or the shares acquired pursuant thereto. The Company shall have no obligation to deliver shares of Stock or to release shares of Stock from an escrow established pursuant to an Award Agreement until the Participating
Company Group’s tax withholding obligations have been satisfied by the Participant. 
 10.2 Withholding in or Directed Sale of
Shares. The Company shall have the right, but not the obligation, to deduct from the shares of Stock issuable to a Participant upon the exercise or vesting of an Award, or to accept from the Participant the tender of, a number of whole shares of
Stock having a Fair Market Value, as determined by the Company, equal to all or any part of the tax withholding obligations of any Participating Company. The Fair Market Value of any shares of Stock withheld or tendered to satisfy any such tax
withholding obligations shall not exceed the amount determined by the applicable minimum statutory withholding rates. The Company may require a Participant to direct a broker, upon the vesting or exercise of an Award, to sell a portion of the shares
subject to the Award determined by the Company in its discretion to be sufficient to cover the tax withholding obligations of any Participating Company and to remit an amount equal to such tax withholding obligations to the Company in cash. 

 

	 	11.	COMPLIANCE WITH SECURITIES LAW. 

The grant of Awards and the issuance of shares of Stock pursuant to any Award shall be subject to compliance with all applicable requirements
of federal, state and foreign law with respect to such securities and the requirements of any stock exchange or market system upon which the Stock may then be listed. In addition, no Award may be exercised or shares issued pursuant to an Award
unless (a) a registration statement under the Securities Act shall at the time of such exercise or issuance be in effect with respect to the shares issuable pursuant to the Award or (b) in the opinion of legal counsel to the Company, the
shares issuable pursuant to the Award may be issued in accordance with the terms of an applicable exemption from the registration requirements of the Securities Act. The inability of the Company to obtain from any regulatory body having jurisdiction
the authority, if any, deemed by the Company’s legal counsel 

  
 18 

 
to be necessary to the lawful issuance and sale of any shares hereunder shall relieve the Company of any liability in respect of the failure to issue or sell such shares as to which such
requisite authority shall not have been obtained. As a condition to issuance of any Stock, the Company may require the Participant to satisfy any qualifications that may be necessary or appropriate, to evidence compliance with any applicable law or
regulation and to make any representation or warranty with respect thereto as may be requested by the Company. 
  

	 	12.	AMENDMENT OR TERMINATION OF PLAN. 

The Board may amend, suspend or terminate the Plan at any time. However, without the approval of the Company’s stockholders, there shall
be (a) no increase in the maximum aggregate number of shares of Stock that may be issued under the Plan (except by operation of the provisions of Sections 4.2 and 4.3), (b) no change in the class of persons eligible to receive
Incentive Stock Options, and (c) no other amendment of the Plan that would require approval of the Company’s stockholders under any applicable law, regulation or rule, including the rules of any stock exchange or quotation system upon
which the Stock may then be listed or quoted. No amendment, suspension or termination of the Plan shall affect any then outstanding Award unless expressly provided by the Board. Except as provided by the next sentence, no amendment, suspension or
termination of the Plan may have a materially adverse effect on any then outstanding Award without the consent of the Participant. Notwithstanding any other provision of the Plan or any Award Agreement to the contrary, the Board may, in its sole and
absolute discretion and without the consent of any Participant, amend the Plan or any Award Agreement, to take effect retroactively or otherwise, as it deems necessary or advisable for the purpose of conforming the Plan or such Award Agreement to
any present or future law, regulation or rule applicable to the Plan, including, but not limited to, Section 409A of the Code. 
  

	 	13.	MISCELLANEOUS PROVISIONS. 

13.1 Repurchase Rights. Shares issued under the Plan may be subject to a right of first refusal, one or more repurchase
options, or other conditions and restrictions as determined by the Board in its discretion at the time the Award is granted. The Company shall have the right to assign at any time any repurchase right it may have, whether or not such right is then
exercisable, to one or more persons as may be selected by the Company. Upon request by the Company, each Participant shall execute any agreement evidencing such transfer restrictions prior to the receipt of shares of Stock hereunder and shall
promptly present to the Company any and all certificates representing shares of Stock acquired hereunder for the placement on such certificates of appropriate legends evidencing any such transfer restrictions. 

13.2 Forfeiture Events. The Board may specify in an Award Agreement that the Participant’s rights, payments, and benefits with
respect to an Award shall be subject to reduction, cancellation, forfeiture, or recoupment upon the occurrence of specified events, in addition to any otherwise applicable vesting or performance conditions of an Award. Such events may include, but
shall not be limited to, termination of Service for Cause or any act by a Participant, whether before or after termination of Service, that would constitute Cause for termination of Service. 

  
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 13.3 Provision of Information. At least annually, copies of the Company’s balance
sheet and income statement for the just completed fiscal year shall be made available to each Participant and purchaser of shares of Stock upon the exercise of an Award; provided, however, that this requirement shall not apply if all offers and
sales of securities pursuant to the Plan comply with all applicable conditions of Rule 701 under the Securities Act. The Company shall not be required to provide such information to key persons whose duties in connection with the Company assure them
access to equivalent information. The Company shall deliver to each Participant such disclosures as are required in accordance with Rule 701 under the Securities Act. 

13.4 Rights as Employee, Consultant or Director. No person, even though eligible pursuant to Section 5, shall have a right to be
selected as a Participant, or, having been so selected, to be selected again as a Participant. Nothing in the Plan or any Award granted under the Plan shall confer on any Participant a right to remain an Employee, Consultant or Director or interfere
with or limit in any way any right of a Participating Company to terminate the Participant’s Service at any time. To the extent that an Employee of a Participating Company other than the Company receives an Award under the Plan, that Award
shall in no event be understood or interpreted to mean that the Company is the Employee’s employer or that the Employee has an employment relationship with the Company. 

13.5 Rights as a Stockholder. A Participant shall have no rights as a stockholder with respect to any shares covered by an Award until
the date of the issuance of such shares (as evidenced by the appropriate entry on the books of the Company or of a duly authorized transfer agent of the Company). No adjustment shall be made for dividends, distributions or other rights for which the
record date is prior to the date such shares are issued, except as provided in Section 4.3 or another provision of the Plan. 
 13.6
Delivery of Title to Shares. Subject to any governing rules or regulations, the Company shall issue or cause to be issued the shares of Stock acquired pursuant to an Award and shall deliver such shares to or for the benefit of the Participant
by means of one or more of the following: (a) by delivering to the Participant evidence of book entry shares of Stock credited to the account of the Participant, (b) by depositing such shares of Stock for the benefit of the Participant
with any broker with which the Participant has an account relationship, or (c) by delivering such shares of Stock to the Participant in certificate form. 

13.7 Fractional Shares. The Company shall not be required to issue fractional shares upon the exercise or settlement of any Award. 

13.8 Retirement and Welfare Plans. Neither Awards made under this Plan nor shares of Stock or cash paid pursuant to such Awards may be
included as “compensation” for purposes of computing the benefits payable to any Participant under any Participating Company’s retirement plans (both qualified and non-qualified) or welfare benefit plans unless such other plan
expressly provides that such compensation shall be taken into account in computing a Participant’s benefits. 
 13.9
Severability. If any one or more of the provisions (or any part thereof) of this Plan shall be held invalid, illegal or unenforceable in any respect, such provision shall be 

  
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modified so as to make it valid, legal and enforceable, and the validity, legality and enforceability of the remaining provisions (or any part thereof) of the Plan shall not in any way be
affected or impaired thereby. 
 13.10 No Constraint on Corporate Action. Nothing in this Plan shall be construed to: (a) limit,
impair, or otherwise affect the Company’s or another Participating Company’s right or power to make adjustments, reclassifications, reorganizations, or changes of its capital or business structure, or to merge or consolidate, or dissolve,
liquidate, sell, or transfer all or any part of its business or assets; or (b) limit the right or power of the Company or another Participating Company to take any action which such entity deems to be necessary or appropriate. 

13.11 Choice of Law. Except to the extent governed by applicable federal law, the validity, interpretation, construction and
performance of the Plan and each Award Agreement shall be governed by the laws of the State of Delaware, without regard to its conflict of law rules. 

13.12 Stockholder Approval. The Plan or any increase in the maximum aggregate number of shares of Stock issuable thereunder as provided
in Section 4.1 (the “Authorized Shares”) shall be approved by a majority of the outstanding securities of the Company entitled to vote by the later of (a) a period beginning twelve (12) months before and
ending twelve (12) months after the date of adoption thereof by the Board or (b) the first issuance of any security pursuant to the Plan in the State of California (within the meaning of Section 25008 of the California Corporations
Code). Awards granted prior to security holder approval of the Plan or in excess of the Authorized Shares previously approved by the security holders shall become exercisable no earlier than the date of security holder approval of the Plan or such
increase in the Authorized Shares, as the case may be, and such Awards shall be rescinded if such security holder approval is not received in the manner described in the preceding sentence. 

IN WITNESS WHEREOF, the undersigned Secretary of the Company certifies that the foregoing sets forth the Xtera Communications, Inc.
2011 Stock Plan as duly adopted by the Board on September 22, 2011. 
  

	
	 /s/ Paul J. Colan

	Secretary

  
 21 

 PLAN HISTORY 
  

			
	September 22, 2011	  	Board adopts Plan, with an initial reserve of 16,000,000 shares.
		
	September 22, 2011	  	Stockholders of the Company approve Plan.

 THE SECURITIES WHICH ARE THE SUBJECT OF THIS AGREEMENT HAVE BEEN ACQUIRED FOR INVESTMENT AND NOT WITH A VIEW
TO, OR IN CONNECTION WITH, THE SALE OR DISTRIBUTION THEREOF. NO SUCH SALE OR DISPOSITION MAY BE EFFECTED WITHOUT AN EFFECTIVE REGISTRATION STATEMENT RELATED THERETO OR AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION IS NOT
REQUIRED UNDER THE SECURITIES ACT OF 1933. 
 THE SECURITIES WHICH ARE THE SUBJECT OF THIS AGREEMENT HAVE NOT BEEN QUALIFIED WITH THE COMMISSIONER OF
CORPORATIONS OF THE STATE OF CALIFORNIA AND THE ISSUANCE OF SUCH SECURITIES OR THE PAYMENT OR RECEIPT OF ANY PART OF THE CONSIDERATION THEREFOR PRIOR TO SUCH QUALIFICATION IS UNLAWFUL, UNLESS THE SALE OF SECURITIES IS EXEMPT FROM QUALIFICATION BY
SECTION 25100, 25102, OR 25105 OF THE CALIFORNIA CORPORATIONS CODE. THE RIGHTS OF ALL PARTIES TO THIS AGREEMENT ARE EXPRESSLY CONDITIONED UPON SUCH QUALIFICATION BEING OBTAINED, UNLESS THE SALE IS SO EXEMPT. 

XTERA COMMUNICATIONS, INC. 

STOCK OPTION AGREEMENT 

Xtera Communications, Inc. has granted to the Participant named in the Notice of Grant of Stock Option (the “Grant
Notice”) to which this Stock Option Agreement (the “Option Agreement”) is attached an option (the “Option”) to purchase certain shares of Stock upon the
terms and conditions set forth in the Grant Notice and this Option Agreement. The Option has been granted pursuant to and shall in all respects be subject to the terms and conditions of the Xtera Communications, Inc. 2011 Stock Plan (the
“Plan”), as amended to the Date of Grant, the provisions of which are incorporated herein by reference. By signing the Grant Notice, the Participant: (a) acknowledges receipt of, and represents that the
Participant has read and is familiar with, the Grant Notice, this Option Agreement and the Plan, (b) accepts the Option subject to all of the terms and conditions of the Grant Notice, this Option Agreement and the Plan, and (c) agrees to
accept as binding, conclusive and final all decisions or interpretations of the Board upon any questions arising under the Grant Notice, this Option Agreement or the Plan. 
  

	 	1.	DEFINITIONS AND CONSTRUCTION. 

1.1 Definitions. Unless otherwise defined herein, capitalized terms shall have the meanings assigned to such terms in the
Grant Notice or the Plan. 
 1.2 Construction. Captions and titles contained herein are for convenience only and shall
not affect the meaning or interpretation of any provision of this Option Agreement. Except when otherwise indicated by the context, the singular shall include the plural and the plural shall include the singular. Use of the term “or” is
not intended to be exclusive, unless the context clearly requires otherwise. 
  

	 	2.	TAX CONSEQUENCES. 

2.1 Tax Status of Option. This Option is intended to have the tax status designated in the Grant Notice. 

(a) Incentive Stock Option. If the Grant Notice so designates, this Option is intended to be an Incentive Stock Option
within the meaning of Section 422(b) of the Code, but the 

  
 1 

 
Company does not represent or warrant that this Option qualifies as such. The Participant should consult with the Participant’s own tax advisor regarding the tax effects of this Option and
the requirements necessary to obtain favorable income tax treatment under Section 422 of the Code, including, but not limited to, holding period requirements. (NOTE TO PARTICIPANT: If the Option is exercised more than three (3) months
after the date on which you cease to be an Employee (other than by reason of your death or permanent and total disability as defined in Section 22(e)(3) of the Code), the Option will be treated as a Nonstatutory Stock Option and not as an
Incentive Stock Option to the extent required by Section 422 of the Code.) 
 (b) Nonstatutory Stock Option. If the
Grant Notice so designates, this Option is intended to be a Nonstatutory Stock Option and shall not be treated as an Incentive Stock Option within the meaning of Section 422(b) of the Code. 

2.2 ISO Fair Market Value Limitation. If the Grant Notice designates this Option as an Incentive Stock Option, then to the
extent that the Option (together with all Incentive Stock Options granted to the Participant under all stock option plans of the Participating Company Group, including the Plan) becomes exercisable for the first time during any calendar year for
shares having a Fair Market Value greater than $100,000, the portion of such options which exceeds such amount will be treated as Nonstatutory Stock Options. For purposes of this Section 2, options designated as Incentive Stock Options
are taken into account in the order in which they were granted, and the Fair Market Value of stock is determined as of the time the option with respect to such stock is granted. If the Code is amended to provide for a different limitation from that
set forth in this Section 2, such different limitation shall be deemed incorporated herein effective as of the date required or permitted by such amendment to the Code. If the Option is treated as an Incentive Stock Option in part and as
a Nonstatutory Stock Option in part by reason of the limitation set forth in this Section 2, the Participant may designate which portion of such Option the Participant is exercising. In the absence of such designation, the Participant
shall be deemed to have exercised the Incentive Stock Option portion of the Option first. Separate certificates representing each such portion shall be issued upon the exercise of the Option. (NOTE TO PARTICIPANT: If the aggregate Exercise Price of
the Option (that is, the Exercise Price multiplied by the Number of Option Shares) plus the aggregate exercise price of any other Incentive Stock Options you hold (whether granted pursuant to the Plan or any other stock option plan of the
Participating Company Group) is greater than $100,000, you should contact the Chief Financial Officer of the Company to ascertain whether the entire Option qualifies as an Incentive Stock Option.) 

 

	 	3.	ADMINISTRATION. 

 All questions of interpretation
concerning the Grant Notice, this Option Agreement, the Plan or any other form of agreement or other document employed by the Company in the administration of the Plan or the Option shall be determined by the Board. All such determinations by the
Board shall be final, binding and conclusive upon all persons having an interest in the Option, unless fraudulent or made in bad faith. Any and all actions, decisions and determinations taken or made by the Board in the exercise of its discretion
pursuant to the Plan or the Option or other agreement thereunder (other than determining questions of interpretation pursuant to the preceding sentence) shall be final, binding and conclusive upon all persons having an interest in the Option. Any
Officer shall have the authority to act on behalf of the Company with respect to any matter, right, obligation, or election which is the responsibility of or which is allocated to the Company herein, provided the Officer has apparent authority with
respect to such matter, right, obligation, or election. 

  
 2 

	 	4.	EXERCISE OF THE OPTION. 

4.1 Right to Exercise. Except as otherwise provided herein, the Option shall be exercisable on and after the Initial Vesting Date
and prior to the termination of the Option (as provided in Section 6) in an amount not to exceed the number of Vested Shares less the number of shares previously acquired upon exercise of the Option, subject to the Company’s
repurchase rights set forth in Section 11. In no event shall the Option be exercisable for more shares than the Number of Option Shares, as adjusted pursuant to Section 9. 

4.2 Method of Exercise. Exercise of the Option shall be by means of electronic or written notice (the
“Exercise Notice”) in a form authorized by the Company. An electronic Exercise Notice must be digitally signed or authenticated by the Participant in such manner as required by the notice and transmitted to the
Company or an authorized representative of the Company (including a third-party administrator designated by the Company). In the event that the Participant is not authorized or is unable to provide an electronic Exercise Notice, the Option shall be
exercised by a written Exercise Notice addressed to the Company, which shall be signed by the Participant and delivered in person, by certified or registered mail, return receipt requested, by confirmed facsimile transmission, or by such other means
as the Company may permit, to the Company, or an authorized representative of the Company (including a third-party administrator designated by the Company). Each Exercise Notice, whether electronic or written, must state the Participant’s
election to exercise the Option, the number of whole shares of Stock for which the Option is being exercised and such other representations and agreements as to the Participant’s investment intent with respect to such shares as may be required
pursuant to the provisions of this Option Agreement. Further, each Exercise Notice must be received by the Company prior to the termination of the Option as set forth in Section 6 and must be accompanied by full payment of the aggregate
Exercise Price for the number of shares of Stock being purchased. The Option shall be deemed to be exercised upon receipt by the Company of such electronic or written Exercise Notice and the aggregate Exercise Price. 

4.3 Payment of Exercise Price. 

(a) Forms of Consideration Authorized. Except as otherwise provided below, payment of the aggregate Exercise Price for
the number of shares of Stock for which the Option is being exercised shall be made (i) in cash, by check or in cash equivalent, (ii) if permitted by the Company and subject to the limitations contained in Section 4.3(b), by
means of (1) a Stock Tender Exercise, (2) a Cashless Exercise or (3) a Net-Exercise; or (iii) by any combination of the foregoing. 

(b) Limitations on Forms of Consideration. The Company reserves, at any and all times, the right, in the Company’s sole
and absolute discretion, to establish, decline to approve or terminate any program or procedure providing for payment of the Exercise Price through any of the means described below, including with respect to the Participant notwithstanding that such
program or procedures may be available to others. 
 (i) Stock Tender Exercise. A “Stock Tender
Exercise” means the delivery of a properly executed Exercise Notice accompanied by (1) the Participant’s tender to the Company, or attestation to the ownership, in a form acceptable to the Company of whole shares of
Stock having a Fair Market Value that does not exceed the aggregate Exercise Price for the shares with respect to which the Option is exercised, and (2) the Participant’s payment to the Company in cash of the remaining balance of such
aggregate Exercise Price not satisfied by such shares’ Fair Market Value. A Stock Tender Exercise shall not be permitted if it would constitute a violation of the provisions of any law, regulation or agreement restricting the redemption of the
Company’s stock. If required by the Company, the Option may not be exercised by tender to the Company, or attestation to the ownership, of 

  
 3 

 
shares of Stock unless such shares either have been owned by the Participant for a period of time required by the Company (and not used for another option exercise by attestation during such
period) or were not acquired, directly or indirectly, from the Company. 
 (ii) Cashless Exercise. A Cashless Exercise shall be
permitted only upon the class of shares subject to the Option becoming publicly traded in an established securities market. A “Cashless Exercise” means the delivery of a properly executed Exercise Notice
together with irrevocable instructions to a broker in a form acceptable to the Company providing for the assignment to the Company of the proceeds of a sale or loan with respect to shares of Stock acquired upon the exercise of the Option in an
amount not less than the aggregate Exercise Price for such shares (including, without limitation, through an exercise complying with the provisions of Regulation T as promulgated from time to time by the Board of Governors of the Federal
Reserve System). 
 (iii) Net-Exercise. A “Net-Exercise” means the delivery of a properly
executed Exercise Notice electing a procedure pursuant to which (1) the Company will reduce the number of shares otherwise issuable to the Participant upon the exercise of the Option by the largest whole number of shares having a Fair Market
Value that does not exceed the aggregate Exercise Price for the shares with respect to which the Option is exercised, and (2) the Participant shall pay to the Company in cash the remaining balance of such aggregate Exercise Price not satisfied
by such reduction in the number of whole shares to be issued. Following a Net-Exercise, the number of shares remaining subject to the Option, if any, shall be reduced by the sum of (1) the net number of shares issued to the Participant upon
such exercise, and (2) the number of shares deducted by the Company for payment of the aggregate Exercise Price. 
 4.4 Tax
Withholding. 
 (a) In General. At the time the Option is exercised, in whole or in part, or at any time
thereafter as requested by a Participating Company, the Participant hereby authorizes withholding from payroll and any other amounts payable to the Participant, and otherwise agrees to make adequate provision for any sums required to satisfy the
federal, state, local and foreign tax (including any social insurance) withholding obligations of the Participating Company Group, if any, which arise in connection with the Option. The Company shall have no obligation to deliver shares of Stock
until the tax withholding obligations of the Participating Company Group have been satisfied by the Participant. 
 (b) Withholding
in or Directed Sale of Shares. The Company shall have the right, but not the obligation, to require the Participant to satisfy all or any portion of a Participating Company’s tax withholding obligations upon exercise of the
Option by deducting from the shares of Stock otherwise issuable to the Participant upon such exercise a number of whole shares having a fair market value, as determined by the Company as of the date of exercise, not in excess of the amount of such
tax withholding obligations determined by the applicable minimum statutory withholding rates. The Company may require the Participant to direct a broker, upon the exercise of the Option, to sell a portion of the shares subject to the Option
determined by the Company in its discretion to be sufficient to cover the tax withholding obligations of any Participating Company and to remit an amount equal to such tax withholding obligations to the Company in cash. 

17.5 Beneficial Ownership of Shares; Certificate Registration. The Participant hereby authorizes the Company, in its sole
discretion, to deposit for the benefit of the Participant with any broker with which the Participant has an account relationship of which the Company has notice any or all shares acquired by the Participant pursuant to the exercise of the Option.
Except as provided by the preceding sentence, a certificate for the shares as to which the Option is exercised shall be registered in the name of the Participant, or, if applicable, in the names of the heirs of the Participant. 

  
 4 

 4.6 Restrictions on Grant of the Option and Issuance of Shares. The grant of
the Option and the issuance of shares of Stock upon exercise of the Option shall be subject to compliance with all applicable requirements of federal, state or foreign law with respect to such securities. The Option may not be exercised if the
issuance of shares of Stock upon exercise would constitute a violation of any applicable federal, state or foreign securities laws or other law or regulations or the requirements of any stock exchange or market system upon which the Stock may then
be listed. In addition, the Option may not be exercised unless (i) a registration statement under the Securities Act shall at the time of exercise of the Option be in effect with respect to the shares issuable upon exercise of the Option or
(ii) in the opinion of legal counsel to the Company, the shares issuable upon exercise of the Option may be issued in accordance with the terms of an applicable exemption from the registration requirements of the Securities Act. THE PARTICIPANT
IS CAUTIONED THAT THE OPTION MAY NOT BE EXERCISED UNLESS THE FOREGOING CONDITIONS ARE SATISFIED. ACCORDINGLY, THE PARTICIPANT MAY NOT BE ABLE TO EXERCISE THE OPTION WHEN DESIRED EVEN THOUGH THE OPTION IS VESTED. The inability of the Company to
obtain from any regulatory body having jurisdiction the authority, if any, deemed by the Company’s legal counsel to be necessary to the lawful issuance and sale of any shares subject to the Option shall relieve the Company of any liability in
respect of the failure to issue or sell such shares as to which such requisite authority shall not have been obtained. As a condition to the exercise of the Option, the Company may require the Participant to satisfy any qualifications that may be
necessary or appropriate, to evidence compliance with any applicable law or regulation and to make any representation or warranty with respect thereto as may be requested by the Company. 

4.7 Fractional Shares. The Company shall not be required to issue fractional shares upon the exercise of the Option. 

 

	 	5.	NONTRANSFERABILITY OF THE OPTION. 

During the lifetime of the Participant, the Option shall be exercisable only by the Participant or the Participant’s guardian or legal
representative. The Option shall not be subject in any manner to anticipation, alienation, sale, exchange, transfer, assignment, pledge, encumbrance, or garnishment by creditors of the Participant or the Participant’s beneficiary, except
transfer by will or by the laws of descent and distribution. Following the death of the Participant, the Option, to the extent provided in Section 7, may be exercised by the Participant’s legal representative or by any person
empowered to do so under the deceased Participant’s will or under the then applicable laws of descent and distribution. 
  

	 	6.	TERMINATION OF THE OPTION. 

The Option shall terminate and may no longer be exercised after the first to occur of (a) the close of business on the Option Expiration
Date, (b) the close of business on the last date for exercising the Option following termination of the Participant’s Service as described in Section 7, or (c) a Change in Control to the extent provided in
Section 8. 
  

	 	7.	EFFECT OF TERMINATION OF SERVICE. 

20.1 Option Exercisability. The Option shall terminate immediately upon the Participant’s termination of Service to the extent that
it is then unvested and shall be exercisable after the Participant’s termination of Service to the extent it is then vested only during the applicable time period as determined below and thereafter shall terminate. 

(a) Disability. If the Participant’s Service terminates because of the Disability of the Participant, the Option,
to the extent unexercised and exercisable for Vested Shares on 

  
 5 

 
the date on which the Participant’s Service terminated, may be exercised by the Participant (or the Participant’s guardian or legal representative) at any time prior to the expiration
of 12 months after the date on which the Participant’s Service terminated, but in any event no later than the Option Expiration Date. 

(b) Death. If the Participant’s Service terminates because of the death of the Participant, the Option, to the
extent unexercised and exercisable for Vested Shares on the date on which the Participant’s Service terminated, may be exercised by the Participant’s legal representative or other person who acquired the right to exercise the Option by
reason of the Participant’s death at any time prior to the expiration of 12 months after the date on which the Participant’s Service terminated, but in any event no later than the Option Expiration Date. The Participant’s Service
shall be deemed to have terminated on account of death if the Participant dies within three (3) months after the Participant’s termination of Service. 

(c) Termination for Cause. Notwithstanding any other provision of this Option Agreement, if the Participant’s Service is
terminated for Cause, the Option shall terminate in its entirety and cease to be exercisable immediately upon such termination of Service. 

(d) Other Termination of Service. If the Participant’s Service terminates for any reason, except Disability, death
or Cause, the Option, to the extent unexercised and exercisable for Vested Shares by the Participant on the date on which the Participant’s Service terminated, may be exercised by the Participant at any time prior to the expiration of three
(3) months after the date on which the Participant’s Service terminated, but in any event no later than the Option Expiration Date. 

20.2 Extension if Exercise Prevented by Law. Notwithstanding the foregoing other than termination of the
Participant’s Service for Cause, if the exercise of the Option within the applicable time periods set forth in Section 7.1 is prevented by the provisions of Section 4.6, the Option shall remain exercisable until the
later of (a) 30 days after the date such exercise first would no longer be prevented by such provisions or (b) the end of the applicable time period under Section 7.1, but in any event no later than the Option Expiration Date.

  

	 	8.	EFFECT OF CHANGE IN CONTROL. 

In the event of a Change in Control, except to the extent that the Board determines to settle the Option in accordance with
Section 9.1(c) of the Plan, the surviving, continuing, successor, or purchasing corporation or other business entity or parent thereof, as the case may be (the “Acquiror”), may, without the consent
of the Participant, assume or continue in full force and effect the Company’s rights and obligations under all or any portion of the Option or substitute for all or any portion of the Option a substantially equivalent option for the
Acquiror’s stock. For purposes of this Section 8, the Option or any portion thereof shall be deemed assumed if, following the Change in Control, the Option confers the right to receive, subject to the terms and conditions of the
Plan and this Option Agreement, for each share of Stock subject to such portion of the Option immediately prior to the Change in Control, the consideration (whether stock, cash, other securities or property or a combination thereof) to which a
holder of a share of Stock on the effective date of the Change in Control was entitled (and if holders were offered a choice of consideration, the type of consideration chosen by the holders of a majority of the outstanding shares of Stock);
provided, however, that if such consideration is not solely common stock of the Acquiror, the Board may, with the consent of the Acquiror, provide for the consideration to be received upon the exercise of the Option for each share of Stock to
consist solely of common stock of the Acquiror equal in Fair Market Value to the per share consideration received by holders of Stock pursuant to the Change in Control. If any portion of such consideration may be received by holders of Stock
pursuant to the Change in Control on a contingent or delayed basis, the Board may, in its discretion, determine such Fair Market 

  
 6 

 
Value per share as of the time of the Change in Control on the basis of the Board’s good faith estimate of the present value of the probable future payment of such consideration. The Option
shall terminate and cease to be outstanding effective as of the time of consummation of the Change in Control to the extent that the Option is neither assumed or continued by the Acquiror in connection with the Change in Control nor exercised as of
the time of the Change in Control. Notwithstanding the foregoing, shares acquired upon exercise of the Option prior to the Change in Control and any consideration received pursuant to the Change in Control with respect to such shares shall continue
to be subject to all applicable provisions of this Option Agreement except as otherwise provided herein. 
  

	 	9.	ADJUSTMENTS FOR CHANGES IN CAPITAL STRUCTURE. 

Subject to any required action by the stockholders of the Company and the requirements of Sections 409A and 424 of the Code to the extent
applicable, in the event of any change in the Stock effected without receipt of consideration by the Company, whether through merger, consolidation, reorganization, reincorporation, recapitalization, reclassification, stock dividend, stock split,
reverse stock split, split-up, split-off, spin-off, combination of shares, exchange of shares, or similar change in the capital structure of the Company, or in the event of payment of a dividend or distribution to the stockholders of the Company in
a form other than Stock (excepting normal cash dividends) that has a material effect on the Fair Market Value of shares of Stock, appropriate and proportionate adjustments shall be made in the number, Exercise Price and kind of shares subject to the
Option, in order to prevent dilution or enlargement of the Participant’s rights under the Option. For purposes of the foregoing, conversion of any convertible securities of the Company shall not be treated as “effected without receipt of
consideration by the Company.” Any fractional share resulting from an adjustment pursuant to this Section 9 shall be rounded down to the nearest whole number, and the Exercise Price shall be rounded up to the nearest whole cent. In
no event may the Exercise Price be decreased to an amount less than the par value, if any, of the stock subject to the Option. Such adjustments shall be determined by the Board, and its determination shall be final, binding and conclusive. 

 

	 	10.	RIGHTS AS A STOCKHOLDER, DIRECTOR, EMPLOYEE OR
CONSULTANT. 

 The Participant shall have no rights as a
stockholder with respect to any shares covered by the Option until the date of the issuance of the shares for which the Option has been exercised (as evidenced by the appropriate entry on the books of the Company or of a duly authorized transfer
agent of the Company). No adjustment shall be made for dividends, distributions or other rights for which the record date is prior to the date the shares are issued, except as provided in Section 9. If the Participant is an Employee, the
Participant understands and acknowledges that, except as otherwise provided in a separate, written employment agreement between a Participating Company and the Participant, the Participant’s employment is “at will” and is for no
specified term. Nothing in this Option Agreement shall confer upon the Participant any right to continue in the Service of a Participating Company or interfere in any way with any right of the Participating Company Group to terminate the
Participant’s Service as a Director, an Employee or Consultant, as the case may be, at any time. 
  

	 	11.	RIGHT OF FIRST REFUSAL. 

11.1 Grant of Right of First Refusal. Except as provided in Section 11.7 and Section 16 below, in
the event the Participant, the Participant’s legal representative, or other holder of shares acquired upon exercise of the Option proposes to sell, exchange, transfer, pledge, or otherwise dispose of any Vested Shares (the
“Transfer Shares”) to any person or entity, including, without limitation, any stockholder of a Participating Company, the Company shall have the right to repurchase the Transfer Shares under the terms and
subject to the conditions set forth in this Section 11 (the “Right of First Refusal”). 

  
 7 

 11.2 Notice of Proposed Transfer. Prior to any proposed transfer of the
Transfer Shares, the Participant shall deliver written notice (the “Transfer Notice”) to the Company describing fully the proposed transfer, including the number of Transfer Shares, the name and address of the
proposed transferee (the “Proposed Transferee”) and, if the transfer is voluntary, the proposed transfer price, and containing such information necessary to show the bona fide nature of the proposed transfer. In
the event of a bona fide gift or involuntary transfer, the proposed transfer price shall be deemed to be the Fair Market Value of the Transfer Shares, as determined by the Board in good faith. If the Participant proposes to transfer any Transfer
Shares to more than one Proposed Transferee, the Participant shall provide a separate Transfer Notice for the proposed transfer to each Proposed Transferee. The Transfer Notice shall be signed by both the Participant and the Proposed Transferee and
must constitute a binding commitment of the Participant and the Proposed Transferee for the transfer of the Transfer Shares to the Proposed Transferee subject only to the Right of First Refusal. 

11.3 Bona Fide Transfer. If the Company determines that the information provided by the Participant in the Transfer
Notice is insufficient to establish the bona fide nature of a proposed voluntary transfer, the Company shall give the Participant written notice of the Participant’s failure to comply with the procedure described in this Section 11,
and the Participant shall have no right to transfer the Transfer Shares without first complying with the procedure described in this Section 11. The Participant shall not be permitted to transfer the Transfer Shares if the proposed
transfer is not bona fide. 
 11.4 Exercise of Right of First Refusal. If the Company determines the proposed transfer
to be bona fide, the Company shall have the right to purchase all, but not less than all, of the Transfer Shares (except as the Company and the Participant otherwise agree) at the purchase price and on the terms set forth in the Transfer Notice by
delivery to the Participant of a notice of exercise of the Right of First Refusal within 30 days after the date the Transfer Notice is delivered to the Company. The Company’s exercise or failure to exercise the Right of First Refusal with
respect to any proposed transfer described in a Transfer Notice shall not affect the Company’s right to exercise the Right of First Refusal with respect to any proposed transfer described in any other Transfer Notice, whether or not such other
Transfer Notice is issued by the Participant or issued by a person other than the Participant with respect to a proposed transfer to the same Proposed Transferee. If the Company exercises the Right of First Refusal, the Company and the Participant
shall thereupon consummate the sale of the Transfer Shares to the Company on the terms set forth in the Transfer Notice within 60 days after the date the Transfer Notice is delivered to the Company (unless a longer period is offered by the Proposed
Transferee); provided, however, that in the event the Transfer Notice provides for the payment for the Transfer Shares other than in cash, the Company shall have the option of paying for the Transfer Shares by the present value cash equivalent of
the consideration described in the Transfer Notice as reasonably determined by the Company. For purposes of the foregoing, cancellation of any indebtedness of the Participant to any Participating Company shall be treated as payment to the
Participant in cash to the extent of the unpaid principal and any accrued interest canceled. Notwithstanding anything contained in this Section 11 to the contrary, the period during which the Company may exercise the Right of First
Refusal and consummate the purchase of the Transfer Shares from the Participant shall terminate no sooner than the completion of a period of eight months following the date on which the Participant acquired the Transfer Shares upon exercise of the
Option. 
 11.5 Failure to Exercise Right of First Refusal. If the Company fails to exercise the Right of First Refusal
in full (or to such lesser extent as the Company and the Participant otherwise agree) within the period specified in Section 11.4 above, the Participant may conclude a transfer to the Proposed Transferee of the Transfer Shares on the
terms and conditions described in the Transfer Notice, provided such transfer occurs not later than 90 days following delivery to the Company of the Transfer Notice or, if applicable, following the end of the period described in the last sentence of
Section 11.4. The Company shall have the right to demand further assurances from the Participant and the Proposed Transferee (in a 

  
 8 

 
form satisfactory to the Company) that the transfer of the Transfer Shares was actually carried out on the terms and conditions described in the Transfer Notice. No Transfer Shares shall be
transferred on the books of the Company until the Company has received such assurances, if so demanded, and has approved the proposed transfer as bona fide. Any proposed transfer on terms and conditions different from those described in the Transfer
Notice, as well as any subsequent proposed transfer by the Participant, shall again be subject to the Right of First Refusal and shall require compliance by the Participant with the procedure described in this Section 11. 

11.6 Transferees of Transfer Shares. All transferees of the Transfer Shares or any interest therein, other than the
Company, shall be required as a condition of such transfer to agree in writing (in a form satisfactory to the Company) that such transferee shall receive and hold such Transfer Shares or interest therein subject to all of the terms and conditions of
this Option Agreement, including this Section 11 providing for the Right of First Refusal with respect to any subsequent transfer. Any sale or transfer of any shares acquired upon exercise of the Option shall be void unless the
provisions of this Section 11 are met. 
 11.7 Transfers Not Subject to Right of First Refusal. The Right
of First Refusal shall not apply to any transfer or exchange of the shares acquired upon exercise of the Option if such transfer or exchange is in connection with an Ownership Change Event. If the consideration received pursuant to such transfer or
exchange consists of stock of a Participating Company, such consideration shall remain subject to the Right of First Refusal unless the provisions of Section 11.9 result in a termination of the Right of First Refusal. 

11.8 Assignment of Right of First Refusal. The Company shall have the right to assign the Right of First Refusal at any
time, whether or not there has been an attempted transfer, to one or more persons as may be selected by the Company. 
 11.9 Early
Termination of Right of First Refusal. The other provisions of this Option Agreement notwithstanding, the Right of First Refusal shall terminate and be of no further force and effect upon (a) the occurrence of a Change in
Control, unless the Acquiror assumes the Company’s rights and obligations under the Option or substitutes a substantially equivalent option for the Acquiror’s stock for the Option, or (b) the existence of a public market for the class
of shares subject to the Right of First Refusal. A “public market” shall be deemed to exist if (i) such stock is listed on a national securities exchange (as that term is used in the Exchange Act) or
(ii) such stock is traded on the over-the-counter market and prices therefor are published daily on business days in a recognized financial journal. 

 

	 	12.	STOCK DISTRIBUTIONS SUBJECT TO OPTION AGREEMENT. 

If, from time to time, there is any stock dividend, stock split or other change, as described in Section 9, in the character or
amount of any of the outstanding stock of the corporation the stock of which is subject to the provisions of this Option Agreement, then in such event any and all new, substituted or additional securities to which the Participant is entitled by
reason of the Participant’s ownership of the shares acquired upon exercise of the Option shall be immediately subject to the Right of First Refusal with the same force and effect as the shares subject to the Right of First Refusal immediately
before such event. 
  

	 	13.	NOTICE OF SALES UPON DISQUALIFYING DISPOSITION. 

The Participant shall dispose of the shares acquired pursuant to the Option only in accordance with the provisions of this Option
Agreement. In addition, if the Grant Notice designates this Option as 

  
 9 

 
an Incentive Stock Option, the Participant shall (a) promptly notify the Chief Financial Officer of the Company if the Participant disposes of any of the shares acquired pursuant to
the Option within one (1) year after the date the Participant exercises all or part of the Option or within two (2) years after the Date of Grant and (b) provide the Company with a description of the circumstances of such disposition.
Until such time as the Participant disposes of such shares in a manner consistent with the provisions of this Option Agreement, unless otherwise expressly authorized by the Company, the Participant shall hold all shares acquired pursuant to the
Option in the Participant’s name (and not in the name of any nominee) for the one-year period immediately after the exercise of the Option and the two-year period immediately after Date of Grant. At any time during the one-year or two-year
periods set forth above, the Company may place a legend on any certificate representing shares acquired pursuant to the Option requesting the transfer agent for the Company’s stock to notify the Company of any such transfers. The obligation of
the Participant to notify the Company of any such transfer shall continue notwithstanding that a legend has been placed on the certificate pursuant to the preceding sentence. 
  

	 	14.	LEGENDS. 

 The Company
may at any time place legends referencing the Right of First Refusal and any applicable federal, state or foreign securities law restrictions on all certificates representing shares of stock subject to the provisions of this Option Agreement. The
Participant shall, at the request of the Company, promptly present to the Company any and all certificates representing shares acquired pursuant to the Option in the possession of the Participant in order to carry out the provisions of this
Section 14. Unless otherwise specified by the Company, legends placed on such certificates may include, but shall not be limited to, the following: 

14.1 “THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE
SOLD, TRANSFERRED, ASSIGNED OR HYPOTHECATED UNLESS THERE IS AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH ACT COVERING SUCH SECURITIES, THE SALE IS MADE IN ACCORDANCE WITH RULE 144 OR RULE 701 UNDER THE ACT, OR THE COMPANY RECEIVES AN OPINION
OF COUNSEL REASONABLY SATISFACTORY TO THE COMPANY, STATING THAT SUCH SALE, TRANSFER, ASSIGNMENT OR HYPOTHECATION IS EXEMPT FROM THE REGISTRATION AND PROSPECTUS DELIVERY REQUIREMENTS OF SUCH ACT.” 

14.2 “THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN RESTRICTIONS ON TRANSFER AND REPURCHASE OPTIONS IN FAVOR OF THE
CORPORATION OR ITS ASSIGNEE SET FORTH IN AN AGREEMENT BETWEEN THE CORPORATION AND THE REGISTERED HOLDER, OR SUCH HOLDER’S PREDECESSOR IN INTEREST, A COPY OF WHICH IS ON FILE AT THE PRINCIPAL OFFICE OF THIS CORPORATION.” 

14.3 “THE SHARES EVIDENCED BY THIS CERTIFICATE WERE ISSUED BY THE CORPORATION TO THE REGISTERED HOLDER UPON EXERCISE OF AN INCENTIVE
STOCK OPTION AS DEFINED IN SECTION 422 OF THE INTERNAL REVENUE CODE OF 1986, AS AMENDED (“ISO”). IN ORDER TO OBTAIN THE PREFERENTIAL TAX TREATMENT AFFORDED TO ISOs, THE SHARES SHOULD NOT BE TRANSFERRED PRIOR TO [INSERT
DISQUALIFYING DISPOSITION DATE HERE]. SHOULD THE REGISTERED HOLDER ELECT TO TRANSFER ANY OF THE SHARES PRIOR TO THIS DATE AND FOREGO ISO TAX TREATMENT, THE TRANSFER AGENT FOR THE SHARES SHALL NOTIFY THE CORPORATION IMMEDIATELY. THE REGISTERED
HOLDER SHALL HOLD ALL SHARES PURCHASED UNDER THE INCENTIVE STOCK OPTION IN THE REGISTERED HOLDER’S NAME (AND NOT IN THE NAME OF ANY NOMINEE) PRIOR TO THIS DATE OR UNTIL TRANSFERRED AS DESCRIBED ABOVE.” 

  
 10 

	 	15.	LOCK-UP AGREEMENT. 

The Participant hereby agrees that in the event of any underwritten public offering of stock, including an initial public offering of stock,
made by the Company pursuant to an effective registration statement filed under the Securities Act, the Participant shall not offer, sell, contract to sell, pledge, hypothecate, grant any option to purchase or make any short sale of, or otherwise
dispose of any shares of stock of the Company or any rights to acquire stock of the Company for such period of time from and after the effective date of such registration statement as may be established by the underwriter for such public offering;
provided, however, that such period of time shall not exceed 180 days from the effective date of the registration statement to be filed in connection with such public offering; provided, further, however, that such 180 day period may be
extended for an additional period, not to exceed 20 days, upon the request of the Company or the underwriter to accommodate regulatory restrictions on (i) the publication or other distribution of research reports and (ii) analyst
recommendations and opinions, including but not limited to, the restrictions contained in FINRA Rule 2711(f)(4) or NYSE Rule 472(f)(4), or any successor provisions or amendments thereto). The foregoing limitation shall not apply to shares
registered in the public offering under the Securities Act. The Participant hereby agrees to enter into any agreement reasonably required by the underwriters to implement the foregoing within a reasonable timeframe if so requested by the Company.

  

	 	16.	RESTRICTIONS ON TRANSFER OF SHARES. 

No shares acquired upon exercise of the Option may be sold, exchanged, transferred (including, without limitation, any transfer to a nominee or
agent of the Participant), assigned, pledged, hypothecated or otherwise disposed of, including by operation of law in any manner which violates any of the provisions of this Option Agreement, and any such attempted disposition shall be void. The
Company shall not be required (a) to transfer on its books any shares which will have been transferred in violation of any of the provisions set forth in this Option Agreement or (b) to treat as owner of such shares or to accord the right
to vote as such owner or to pay dividends to any transferee to whom such shares will have been so transferred. 
  

	 	17.	MISCELLANEOUS PROVISIONS. 

17.1 Termination or Amendment. The Board may terminate or amend the Plan or the Option at any time; provided, however, that except as
provided in Section 8 in connection with a Change in Control, no such termination or amendment may adversely affect the Option or any unexercised portion hereof without the consent of the Participant unless such termination or amendment
is necessary to comply with any applicable law or government regulation, including, but not limited to Section 409A of the Code. No amendment or addition to this Option Agreement shall be effective unless in writing. 

17.2 Compliance with Section 409A. The Company intends that income realized by the Participant pursuant to the Plan and this
Option Agreement will not be subject to taxation under Section 409A of the Code. The provisions of the Plan and this Option Agreement shall be interpreted and construed in favor of satisfying any applicable requirements of Section 409A of
the Code. The Company, in its reasonable discretion, may amend (including retroactively) the Plan and this Agreement in order to conform to the applicable requirements of Section 409A of the Code, including amendments to facilitate the
Participant’s ability to avoid taxation under Section 409A of the Code. However, the preceding provisions shall not be construed as a guarantee by the Company of any particular tax result for

  
 11 

 
income realized by the Participant pursuant to the Plan or this Option Agreement. In any event, and except for the responsibilities of the Company set forth in Section 4.4, no
Participating Company shall be responsible for the payment of any applicable taxes incurred by the Participant on income realized by the Participant pursuant to the Plan or this Option Agreement. 

17.3 Further Instruments. The parties hereto agree to execute such further instruments and to take such further action as may
reasonably be necessary to carry out the intent of this Option Agreement. 
 17.4 Binding Effect. This Option Agreement shall inure
to the benefit of the successors and assigns of the Company and, subject to the restrictions on transfer set forth herein, be binding upon the Participant and the Participant’s heirs, executors, administrators, successors and assigns. 

17.5 Delivery of Documents and Notices. Any document relating to participation in the Plan, or any notice required or permitted
hereunder shall be given in writing and shall be deemed effectively given (except to the extent that this Option Agreement provides for effectiveness only upon actual receipt of such notice) upon personal delivery, electronic delivery at the e-mail
address, if any, provided for the Participant by a Participating Company, or upon deposit in the U.S. Post Office or foreign postal service, by registered or certified mail, or with a nationally recognized overnight courier service, with postage and
fees prepaid, addressed to the other party at the address of such party set forth in the Grant Notice or at such other address as such party may designate in writing from time to time to the other party. 

(a) Description of Electronic Delivery. The Plan documents, which may include but do not necessarily include: the Plan,
the Grant Notice, this Option Agreement, and any reports of the Company provided generally to the Company’s stockholders, may be delivered to the Participant electronically. In addition, if permitted by the Company, the Participant may deliver
electronically the Grant Notice and Exercise Notice called for by Section 4.2 to the Company or to such third party involved in administering the Plan as the Company may designate from time to time. Such means of electronic delivery may
include but do not necessarily include the delivery of a link to a Company intranet or the Internet site of a third party involved in administering the Plan, the delivery of the document via e-mail or such other means of electronic delivery
specified by the Company. 
 (b) Consent to Electronic Delivery. The Participant acknowledges that the Participant has read
Section 17.5(a) of this Option Agreement and consents to the electronic delivery of the Plan documents and, if permitted by the Company, the delivery of the Grant Notice and Exercise Notice, as described in Section 17.5(a).
The Participant acknowledges that he or she may receive from the Company a paper copy of any documents delivered electronically at no cost to the Participant by contacting the Company by telephone or in writing. The Participant further acknowledges
that the Participant will be provided with a paper copy of any documents if the attempted electronic delivery of such documents fails. Similarly, the Participant understands that the Participant must provide the Company or any designated third party
administrator with a paper copy of any documents if the attempted electronic delivery of such documents fails. The Participant may revoke his or her consent to the electronic delivery of documents described in Section 17.5(a) or may
change the electronic mail address to which such documents are to be delivered (if Participant has provided an electronic mail address) at any time by notifying the Company of such revoked consent or revised e-mail address by telephone, postal
service or electronic mail. Finally, the Participant understands that he or she is not required to consent to electronic delivery of documents described in Section 17.5(a). 

17.6 Integrated Agreement. The Grant Notice, this Option Agreement and the Plan, together with any employment, service or other
agreement with the Participant and a Participating 

  
 12 

 
Company referring to the Option, shall constitute the entire understanding and agreement of the Participant and the Participating Company Group with respect to the subject matter contained herein
or therein and supersede any prior agreements, understandings, restrictions, representations, or warranties among the Participant and the Participating Company Group with respect to such subject matter. To the extent contemplated herein or therein,
the provisions of the Grant Notice, the Option Agreement and the Plan shall survive any exercise of the Option and shall remain in full force and effect. 

17.7 Applicable Law. This Option Agreement shall be governed by the laws of the State of Delaware as such laws are applied to
agreements between Delaware residents entered into and to be performed entirely within the State of Delaware. 
 17.8 Counterparts.
The Grant Notice may be executed in counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument. 

  
 13 

									
	Incentive Stock Option	  		 	Participant:	 	  

	Nonstatutory Stock Option	  		 		 		  	
		  		 		 	Date:	  	  

 STOCK OPTION EXERCISE NOTICE 
  

			
	Xtera Communications, Inc.
	Attention:	 	Treasurer

			
	  
	 	
	  
	 	

 Ladies and Gentlemen: 

1. Option. I was granted an option (the “Option”) to purchase shares of the common stock
(the “Shares”) of Xtera Communications, Inc. (the “Company”) pursuant to the Company’s 2011 Stock Plan (the “Plan”), my Notice of
Grant of Stock Option (the “Grant Notice”) and my Stock Option Agreement (the “Option Agreement”) as follows: 

 

			
	Date of Grant:	 	
		
	Number of Option Shares:	 	
		
	Exercise Price per Share:	 	$            

 2. Exercise of Option. I hereby elect to exercise the Option to purchase the following
number of Shares, all of which are Vested Shares, in accordance with the Grant Notice and the Option Agreement: 
  

			
	Total Shares Purchased:	 	
		
	Total Exercise Price (Total Shares X Price per Share)	 	$            

 3. Payments. I enclose payment in full of the total exercise price for the Shares in the
following form(s), as authorized by my Option Agreement: 
  

			
	Cash:	 	$            
		
	Check:	 	$            
		
	Stock Tender Exercise:	 	Contact Plan Administrator
		
	Cashless Exercise:	 	Contact Plan Administrator
		
	Net Exercise:	 	Contact Plan Administrator

 4. Tax Withholding. I authorize payroll withholding and otherwise will make adequate
provision for the federal, state, local and foreign tax withholding obligations of the Company, if any, in connection with the Option. If I am exercising a Nonstatutory Stock Option, I enclose payment in full of my withholding taxes, if any, as
follows: 
 (Contact Plan Administrator for amount of tax due.) 

 

			
	Cash:	  	$            
		
	Check:	  	$            

  
 1 

 5. Participant Information. 

 

			
	My address is:	 	  

		
		 	  

 
			
		
	My Social Security Number is:	 	  

 6. Notice of Disqualifying Disposition. If the Option is an Incentive Stock Option, I
agree that I will promptly notify the Chief Financial Officer of the Company if I transfer any of the Shares within one (1) year from the date I exercise all or part of the Option or within two years of the Date of Grant. 

7. Binding Effect. I agree that the Shares are being acquired in accordance with and subject to the terms, provisions and
conditions of the Grant Notice, the Option Agreement, including the Right of First Refusal set forth therein, and the Plan, to all of which I hereby expressly assent. This Agreement shall inure to the benefit of and be binding upon my heirs,
executors, administrators, successors and assigns. 
 8. Transfer. I understand and acknowledge that the Shares have not been
registered under the Securities Act of 1933, as amended (the “Securities Act”), and that consequently the Shares must be held indefinitely unless they are subsequently registered under the Securities Act, an
exemption from such registration is available, or they are sold in accordance with Rule 144 or Rule 701 under the Securities Act. I further understand and acknowledge that the Company is under no obligation to register the Shares. I
understand that the certificate or certificates evidencing the Shares will be imprinted with legends which prohibit the transfer of the Shares unless they are registered or such registration is not required in the opinion of legal counsel
satisfactory to the Company. 
 I am aware that Rule 144 under the Securities Act, which permits limited public resale of securities
acquired in a nonpublic offering, is not currently available with respect to the Shares and, in any event, is available only if certain conditions are satisfied. I understand that any sale of the Shares that might be made in reliance upon
Rule 144 may only be made in limited amounts in accordance with the terms and conditions of such rule and that a copy of Rule 144 will be delivered to me upon request. 

I understand that I am purchasing the Shares pursuant to the terms of the Plan, the Grant Notice and my Option Agreement, copies of which I
have received and carefully read and understand. 
  

	
	Very truly yours,
	
	  

	(Signature)

  

			
	Receipt of the above is hereby acknowledged.
	
	Xtera Communications, Inc.
		
	By:	 	  

		
	Title:	 	  

		
	Dated:	 	  

  
 2 

 THE SECURITIES WHICH ARE THE SUBJECT OF THIS AGREEMENT HAVE BEEN ACQUIRED FOR INVESTMENT AND NOT WITH A VIEW TO,
OR IN CONNECTION WITH, THE SALE OR DISTRIBUTION THEREOF. NO SUCH SALE OR DISPOSITION MAY BE EFFECTED WITHOUT AN EFFECTIVE REGISTRATION STATEMENT RELATED THERETO OR AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION IS NOT
REQUIRED UNDER THE SECURITIES ACT OF 1933. 
 THE SECURITIES WHICH ARE THE SUBJECT OF THIS AGREEMENT HAVE NOT BEEN QUALIFIED WITH THE COMMISSIONER OF
CORPORATIONS OF THE STATE OF CALIFORNIA AND THE ISSUANCE OF SUCH SECURITIES OR THE PAYMENT OR RECEIPT OF ANY PART OF THE CONSIDERATION THEREFOR PRIOR TO SUCH QUALIFICATION IS UNLAWFUL, UNLESS THE SALE OF SECURITIES IS EXEMPT FROM QUALIFICATION BY
SECTION 25100, 25102, OR 25105 OF THE CALIFORNIA CORPORATIONS CODE. THE RIGHTS OF ALL PARTIES TO THIS AGREEMENT ARE EXPRESSLY CONDITIONED UPON SUCH QUALIFICATION BEING OBTAINED, UNLESS THE SALE IS SO EXEMPT. 

XTERA COMMUNICATIONS, INC. 

STOCK OPTION AGREEMENT 

(Immediately Exercisable) 

Xtera Communications, Inc. has granted to the Participant named in the Notice of Grant of Stock Option (the “Grant
Notice”) to which this Stock Option Agreement (the “Option Agreement”) is attached an option (the “Option”) to purchase certain shares of Stock upon the
terms and conditions set forth in the Grant Notice and this Option Agreement. The Option has been granted pursuant to and shall in all respects be subject to the terms and conditions of the Xtera Communications, Inc. 2011 Stock Plan (the
“Plan”), as amended to the Date of Grant, the provisions of which are incorporated herein by reference. By signing the Grant Notice, the Participant: (a) acknowledges receipt of, and represents that the
Participant has read and is familiar with, the Grant Notice, this Option Agreement and the Plan, (b) accepts the Option subject to all of the terms and conditions of the Grant Notice, this Option Agreement and the Plan, and (c) agrees to
accept as binding, conclusive and final all decisions or interpretations of the Board upon any questions arising under the Grant Notice, this Option Agreement or the Plan. 
  

	 	1.	DEFINITIONS AND CONSTRUCTION. 

1.1 Definitions. Unless otherwise defined herein, capitalized terms shall have the meanings assigned to such terms in the
Grant Notice or the Plan. 
 1.2 Construction. Captions and titles contained herein are for convenience only and shall
not affect the meaning or interpretation of any provision of this Option Agreement. Except when otherwise indicated by the context, the singular shall include the plural and the plural shall include the singular. Use of the term “or” is
not intended to be exclusive, unless the context clearly requires otherwise. 

  
 1 

	 	2.	TAX CONSEQUENCES. 

2.1 Tax Status of Option. This Option is intended to have the tax status designated in the Grant Notice. 

(a) Incentive Stock Option. If the Grant Notice so designates, this Option is intended to be an Incentive Stock Option
within the meaning of Section 422(b) of the Code, but the Company does not represent or warrant that this Option qualifies as such. The Participant should consult with the Participant’s own tax advisor regarding the tax effects of this
Option and the requirements necessary to obtain favorable income tax treatment under Section 422 of the Code, including, but not limited to, holding period requirements. (NOTE TO PARTICIPANT: If the Option is exercised more than three
(3) months after the date on which you cease to be an Employee (other than by reason of your death or permanent and total disability as defined in Section 22(e)(3) of the Code), the Option will be treated as a Nonstatutory Stock Option and
not as an Incentive Stock Option to the extent required by Section 422 of the Code.) 
 (b) Nonstatutory Stock Option.
If the Grant Notice so designates, this Option is intended to be a Nonstatutory Stock Option and shall not be treated as an Incentive Stock Option within the meaning of Section 422(b) of the Code. 

2.2 Election under Section 83(b) of the Code. If the Participant exercises this Option to purchase shares of Stock that are both
nontransferable and subject to a substantial risk of forfeiture, the Participant understands that the Participant should consult with the Participant’s tax advisor regarding the advisability of filing with the Internal Revenue Service an
election under Section 83(b) of the Code, which must be filed no later than thirty (30) days after the date on which the Participant exercises the Option. Shares acquired upon exercise of the Option are nontransferable and subject to a
substantial risk of forfeiture if they are unvested and are subject to a right of the Company to repurchase such shares at the Participant’s original purchase price if the Participant’s Service terminates. Failure to file an election under
Section 83(b), if appropriate, may result in adverse tax consequences to the Participant. However, an election under Section 83(b) may, under certain circumstances, result in adverse tax consequences to the Participant. The Participant
acknowledges that the Participant has been advised to consult with a tax advisor prior to the exercise of the Option regarding the tax consequences to the Participant of the exercise of the Option and the effect of filing or not filing an election
under Section 83(b). AN ELECTION UNDER SECTION 83(b) MUST BE FILED, IF AT ALL, WITHIN 30 DAYS AFTER THE DATE ON WHICH THE PARTICIPANT PURCHASES SHARES. THIS TIME PERIOD CANNOT BE EXTENDED. THE PARTICIPANT ACKNOWLEDGES THAT TIMELY FILING OF A
SECTION 83(b) ELECTION, IF APPROPRIATE, IS THE PARTICIPANT’S SOLE RESPONSIBILITY, EVEN IF THE PARTICIPANT REQUESTS THE COMPANY OR ITS REPRESENTATIVE TO FILE SUCH ELECTION ON HIS OR HER BEHALF. 

2.3 Notice to Company. The Participant will notify the Company in writing if the Participant files an election pursuant to
Section 83(b) of the Code. The Company intends, in the event it does not receive from the Participant evidence of such filing, to claim a tax deduction for any amount which would otherwise be taxable to the Participant in the absence of such an
election. 

  
 2 

 2.4 ISO Fair Market Value Limitation. If the Grant Notice designates this Option as an
Incentive Stock Option, then to the extent that the Option (together with all Incentive Stock Options granted to the Participant under all stock option plans of the Participating Company Group, including the Plan) becomes exercisable for the
first time during any calendar year for shares having a Fair Market Value greater than One Hundred Thousand Dollars ($100,000), the portion of such options which exceeds such amount will be treated as Nonstatutory Stock Options. For purposes of this
Section, options designated as Incentive Stock Options are taken into account in the order in which they were granted, and the Fair Market Value of stock is determined as of the time the option with respect to such stock is granted. If the Code is
amended to provide for a different limitation from that set forth in this Section, such different limitation shall be deemed incorporated herein effective as of the date required or permitted by such amendment to the Code. If the Option is treated
as an Incentive Stock Option in part and as a Nonstatutory Stock Option in part by reason of the limitation set forth in this Section, the Participant may designate which portion of such Option the Participant is exercising. In the absence of such
designation, the Participant shall be deemed to have exercised the Incentive Stock Option portion of the Option first. Separate certificates representing each such portion shall be issued upon the exercise of the Option. (NOTE TO PARTICIPANT: If the
aggregate Exercise Price of the Option (that is, the Exercise Price multiplied by the Number of Option Shares) plus the aggregate exercise price of any other Incentive Stock Options you hold (whether granted pursuant to the Plan or any other stock
option plan of the Participating Company Group) is greater than $100,000, you should contact the Chief Financial Officer of the Company to ascertain whether the entire Option qualifies as an Incentive Stock Option.) 

 

	 	3.	ADMINISTRATION. 

 All
questions of interpretation concerning the Grant Notice, this Option Agreement, the Plan or any other form of agreement or other document employed by the Company in the administration of the Plan or the Option shall be determined by the Board. All
such determinations by the Board shall be final, binding and conclusive upon all persons having an interest in the Option, unless fraudulent or made in bad faith. Any and all actions, decisions and determinations taken or made by the Board in the
exercise of its discretion pursuant to the Plan or the Option or other agreement thereunder (other than determining questions of interpretation pursuant to the preceding sentence) shall be final, binding and conclusive upon all persons having an
interest in the Option. Any Officer shall have the authority to act on behalf of the Company with respect to any matter, right, obligation, or election which is the responsibility of or which is allocated to the Company herein, provided the Officer
has apparent authority with respect to such matter, right, obligation, or election. 
  

	 	4.	EXERCISE OF THE OPTION. 

4.1 Right to Exercise. Except as otherwise provided herein, the Option shall be exercisable on and after the Date of Grant and
prior to the termination of the Option (as provided in Section 6) in an amount not to exceed the total Number of Option Shares less the number of shares previously acquired upon exercise of the Option, subject to the Company’s repurchase
rights set forth in Sections 11 and 12. In no event shall the Option be exercisable for more shares than the Number of Option Shares, as adjusted pursuant to Section 9. 

  
 3 

 4.2 Method of Exercise. Exercise of the Option shall be by means of
electronic or written notice (the “Exercise Notice”) in a form authorized by the Company. An electronic Exercise Notice must be digitally signed or authenticated by the Participant in such manner as required by
the notice and transmitted to the Company or an authorized representative of the Company (including a third-party administrator designated by the Company). In the event that the Participant is not authorized or is unable to provide an electronic
Exercise Notice, the Option shall be exercised by a written Exercise Notice addressed to the Company, which shall be signed by the Participant and delivered in person, by certified or registered mail, return receipt requested, by confirmed facsimile
transmission, or by such other means as the Company may permit, to the Company, or an authorized representative of the Company (including a third-party administrator designated by the Company). Each Exercise Notice, whether electronic or written,
must state the Participant’s election to exercise the Option, the number of whole shares of Stock for which the Option is being exercised and such other representations and agreements as to the Participant’s investment intent with respect
to such shares as may be required pursuant to the provisions of this Option Agreement. Further, each Exercise Notice must be received by the Company prior to the termination of the Option as set forth in Section 6 and must be accompanied by
(a) full payment of the aggregate Exercise Price for the number of shares of Stock being purchased and (b) if the Option is exercised with respect to any Unvested Shares (as defined in Section 11.1), an Assignment Separate from
Certificate duly endorsed (with date and number of shares blank) in the form attached to the Grant Notice. The Option shall be deemed to be exercised upon receipt by the Company of such electronic or written Exercise Notice, the aggregate Exercise
Price and, if required hereby, such duly endorsed Assignment Separate from Certificate. 
 4.3 Payment of Exercise Price. 

(a) Forms of Consideration Authorized. Except as otherwise provided below, payment of the aggregate Exercise Price for
the number of shares of Stock for which the Option is being exercised shall be made (i) in cash, by check or in cash equivalent, (ii) if permitted by the Company and subject to the limitations contained in Section 4.3(b), by means of
(1) a Stock Tender Exercise, (2) a Cashless Exercise or (3) a Net-Exercise; or (iii) by any combination of the foregoing. 

(b) Limitations on Forms of Consideration. The Company reserves, at any and all times, the right, in the Company’s sole
and absolute discretion, to establish, decline to approve or terminate any program or procedure providing for payment of the Exercise Price through any of the means described below, including with respect to the Participant notwithstanding that such
program or procedures may be available to others. 
 (i) Stock Tender Exercise. A “Stock Tender
Exercise” means the delivery of a properly executed Exercise Notice accompanied by (1) the Participant’s tender to the Company, or attestation to the ownership, in a form acceptable to the Company of whole shares of
Stock having a Fair Market Value that does not exceed the aggregate Exercise Price for the shares with respect to which the Option is exercised, and (2) the Participant’s 

  
 4 

 
payment to the Company in cash of the remaining balance of such aggregate Exercise Price not satisfied by such shares’ Fair Market Value. A Stock Tender Exercise shall not be permitted if it
would constitute a violation of the provisions of any law, regulation or agreement restricting the redemption of the Company’s stock. If required by the Company, the Option may not be exercised by tender to the Company, or attestation to the
ownership, of shares of Stock unless such shares either have been owned by the Participant for a period of time required by the Company (and not used for another option exercise by attestation during such period) or were not acquired, directly or
indirectly, from the Company. 
 (ii) Cashless Exercise. A Cashless Exercise shall be permitted only upon the class of shares
subject to the Option becoming publicly traded in an established securities market. A “Cashless Exercise” means the delivery of a properly executed Exercise Notice together with irrevocable instructions to a
broker in a form acceptable to the Company providing for the assignment to the Company of the proceeds of a sale or loan with respect to shares of Stock acquired upon the exercise of the Option in an amount not less than the aggregate Exercise Price
for such shares (including, without limitation, through an exercise complying with the provisions of Regulation T as promulgated from time to time by the Board of Governors of the Federal Reserve System). 

(iii) Net-Exercise. A “Net-Exercise” means the delivery of a properly executed Exercise Notice
electing a procedure pursuant to which (1) the Company will reduce the number of shares otherwise issuable to the Participant upon the exercise of the Option by the largest whole number of shares having a Fair Market Value that does not exceed
the aggregate Exercise Price for the shares with respect to which the Option is exercised, and (2) the Participant shall pay to the Company in cash the remaining balance of such aggregate Exercise Price not satisfied by such reduction in the
number of whole shares to be issued. Following a Net-Exercise, the number of shares remaining subject to the Option, if any, shall be reduced by the sum of (1) the net number of shares issued to the Participant upon such exercise, and
(2) the number of shares deducted by the Company for payment of the aggregate Exercise Price. 
 4.4 Tax
Withholding. 
 (a) In General. At the time the Option is exercised, in whole or in part, or at any time
thereafter as requested by a Participating Company, the Participant hereby authorizes withholding from payroll and any other amounts payable to the Participant, and otherwise agrees to make adequate provision for any sums required to satisfy the
federal, state, local and foreign tax (including any social insurance) withholding obligations of the Participating Company Group, if any, which arise in connection with the Option. The Company shall have no obligation to deliver shares of Stock
until the tax withholding obligations of the Participating Company Group have been satisfied by the Participant. 
 (b) Withholding
in or Directed Sale of Shares. The Company shall have the right, but not the obligation, to require the Participant to satisfy all or any portion of a Participating Company’s tax withholding obligations upon exercise of the
Option by deducting from the shares of Stock otherwise issuable to the Participant upon such exercise a number of whole shares having a fair market value, as determined by the Company as of the date of exercise, not in excess of the amount of such
tax withholding obligations determined by the 

  
 5 

 
applicable minimum statutory withholding rates. The Company may require the Participant to direct a broker, upon the exercise of the Option, to sell a portion of the shares subject to the Option
determined by the Company in its discretion to be sufficient to cover the tax withholding obligations of any Participating Company and to remit an amount equal to such tax withholding obligations to the Company in cash. 

4.5 Beneficial Ownership of Shares; Certificate Registration. The Participant hereby authorizes the Company, in its sole
discretion, to deposit the shares acquired pursuant to the exercise of the Option with the Company’s transfer agent, including any successor transfer agent, to be held in book entry form during the term of the Escrow pursuant to
Section 14. Furthermore, the Participant hereby authorizes the Company, in its sole discretion, to deposit, following the term of the Escrow, for the benefit of the Participant with any broker with which the Participant has an account
relationship of which the Company has notice any or all such shares which are no longer subject to the Escrow. Except as provided by the foregoing, a certificate for the shares shall be registered in the name of the Participant, or, if applicable,
in the names of the heirs of the Participant. 
 4.6 Restrictions on Grant of the Option and Issuance of Shares. The
grant of the Option and the issuance of shares of Stock upon exercise of the Option shall be subject to compliance with all applicable requirements of federal, state or foreign law with respect to such securities. The Option may not be exercised if
the issuance of shares of Stock upon exercise would constitute a violation of any applicable federal, state or foreign securities laws or other law or regulations or the requirements of any stock exchange or market system upon which the Stock may
then be listed. In addition, the Option may not be exercised unless (i) a registration statement under the Securities Act shall at the time of exercise of the Option be in effect with respect to the shares issuable upon exercise of the Option
or (ii) in the opinion of legal counsel to the Company, the shares issuable upon exercise of the Option may be issued in accordance with the terms of an applicable exemption from the registration requirements of the Securities Act. THE
PARTICIPANT IS CAUTIONED THAT THE OPTION MAY NOT BE EXERCISED UNLESS THE FOREGOING CONDITIONS ARE SATISFIED. ACCORDINGLY, THE PARTICIPANT MAY NOT BE ABLE TO EXERCISE THE OPTION WHEN DESIRED EVEN THOUGH THE OPTION IS VESTED. The inability of the
Company to obtain from any regulatory body having jurisdiction the authority, if any, deemed by the Company’s legal counsel to be necessary to the lawful issuance and sale of any shares subject to the Option shall relieve the Company of any
liability in respect of the failure to issue or sell such shares as to which such requisite authority shall not have been obtained. As a condition to the exercise of the Option, the Company may require the Participant to satisfy any qualifications
that may be necessary or appropriate, to evidence compliance with any applicable law or regulation and to make any representation or warranty with respect thereto as may be requested by the Company. 

4.7 Fractional Shares. The Company shall not be required to issue fractional shares upon the exercise of the Option. 

 

	 	5.	NONTRANSFERABILITY OF THE OPTION. 

During the lifetime of the Participant, the Option shall be exercisable only by the Participant or the Participant’s guardian or legal
representative. The Option shall not be subject 

  
 6 

 
in any manner to anticipation, alienation, sale, exchange, transfer, assignment, pledge, encumbrance, or garnishment by creditors of the Participant or the Participant’s beneficiary, except
transfer by will or by the laws of descent and distribution. Following the death of the Participant, the Option, to the extent provided in Section 7, may be exercised by the Participant’s legal representative or by any person empowered to
do so under the deceased Participant’s will or under the then applicable laws of descent and distribution. 
  

	 	6.	TERMINATION OF THE OPTION. 

The Option shall terminate and may no longer be exercised after the first to occur of (a) the close of business on the Option Expiration
Date, (b) the close of business on the last date for exercising the Option following termination of the Participant’s Service as described in Section 7, or (c) a Change in Control to the extent provided in Section 8. 

 

	 	7.	EFFECT OF TERMINATION OF SERVICE. 

7.1 Option Exercisability. The Option shall terminate immediately upon the Participant’s termination of Service to the extent that
it is then unvested and shall be exercisable after the Participant’s termination of Service to the extent it is then vested only during the applicable time period as determined below and thereafter shall terminate. 

(a) Disability. If the Participant’s Service terminates because of the Disability of the Participant, the Option,
to the extent unexercised and exercisable for Vested Shares on the date on which the Participant’s Service terminated, may be exercised by the Participant (or the Participant’s guardian or legal representative) at any time prior to the
expiration of twelve (12) months after the date on which the Participant’s Service terminated, but in any event no later than the Option Expiration Date. 

(b) Death. If the Participant’s Service terminates because of the death of the Participant, the Option, to the
extent unexercised and exercisable for Vested Shares on the date on which the Participant’s Service terminated, may be exercised by the Participant’s legal representative or other person who acquired the right to exercise the Option by
reason of the Participant’s death at any time prior to the expiration of twelve (12) months after the date on which the Participant’s Service terminated, but in any event no later than the Option Expiration Date. The
Participant’s Service shall be deemed to have terminated on account of death if the Participant dies within three (3) months after the Participant’s termination of Service. 

(c) Termination for Cause. Notwithstanding any other provision of this Option Agreement, if the Participant’s Service is
terminated for Cause, the Option shall terminate in its entirety and cease to be exercisable immediately upon such termination of Service. 

(d) Other Termination of Service. If the Participant’s Service terminates for any reason, except Disability, death
or Cause, the Option, to the extent unexercised and exercisable for Vested Shares by the Participant on the date on which the Participant’s Service terminated, may be exercised by the Participant at any time prior to the earlier of (i) the
expiration of three (3) months after the date on which the Participant’s Service terminated or (ii) the Option Expiration Date. 

7.2 Extension if Exercise Prevented by Law. Notwithstanding the foregoing other than termination of the
Participant’s Service for Cause, if the exercise of the Option within the applicable time periods set forth in Section 7.1 is prevented by the provisions of Section 4.6, the Option shall remain exercisable until the later of
(a) thirty (30) days after the date such exercise first would no longer be prevented by such provisions or (b) the end of the applicable time period under Section 7.1, but in any event no later than the Option Expiration Date.

  
 7 

	 	8.	EFFECT OF CHANGE IN CONTROL. 

In the event of a Change in Control, except to the extent that the Board determines to settle the Option in accordance with Section 9.1(c)
of the Plan, the surviving, continuing, successor, or purchasing corporation or other business entity or parent thereof, as the case may be (the “Acquiror”), may, without the consent of the Participant, assume
or continue in full force and effect the Company’s rights and obligations under all or any portion of the Option or substitute for all or any portion of the Option a substantially equivalent option for the Acquiror’s stock. For purposes of
this Section, the Option or any portion thereof shall be deemed assumed if, following the Change in Control, the Option confers the right to receive, subject to the terms and conditions of the Plan and this Option Agreement, for each share of Stock
subject to such portion of the Option immediately prior to the Change in Control, the consideration (whether stock, cash, other securities or property or a combination thereof) to which a holder of a share of Stock on the effective date of the
Change in Control was entitled (and if holders were offered a choice of consideration, the type of consideration chosen by the holders of a majority of the outstanding shares of Stock); provided, however, that if such consideration is not solely
common stock of the Acquiror, the Board may, with the consent of the Acquiror, provide for the consideration to be received upon the exercise of the Option for each share of Stock to consist solely of common stock of the Acquiror equal in Fair
Market Value to the per share consideration received by holders of Stock pursuant to the Change in Control. If any portion of such consideration may be received by holders of Stock pursuant to the Change in Control on a contingent or delayed basis,
the Board may, in its discretion, determine such Fair Market Value per share as of the time of the Change in Control on the basis of the Board’s good faith estimate of the present value of the probable future payment of such consideration. The
Option shall terminate and cease to be outstanding effective as of the time of consummation of the Change in Control to the extent that the Option is neither assumed or continued by the Acquiror in connection with the Change in Control nor exercised
as of the time of the Change in Control. Notwithstanding the foregoing, shares acquired upon exercise of the Option prior to the Change in Control and any consideration received pursuant to the Change in Control with respect to such shares shall
continue to be subject to all applicable provisions of this Option Agreement except as otherwise provided herein. 
  

	 	9.	ADJUSTMENTS FOR CHANGES IN CAPITAL STRUCTURE. 

Subject to any required action by the stockholders of the Company and the requirements of Sections 409A and 424 of the Code to the extent
applicable, in the event of any change in the Stock effected without receipt of consideration by the Company, whether through merger, consolidation, reorganization, reincorporation, recapitalization, reclassification, stock dividend, stock split,
reverse stock split, split-up, split-off, spin-off, combination of shares, exchange of shares, or similar change in the capital structure of the Company, or in the event of payment of a 

  
 8 

 
dividend or distribution to the stockholders of the Company in a form other than Stock (excepting normal cash dividends) that has a material effect on the Fair Market Value of shares of Stock,
appropriate and proportionate adjustments shall be made in the number, Exercise Price and kind of shares subject to the Option, in order to prevent dilution or enlargement of the Participant’s rights under the Option. For purposes of the
foregoing, conversion of any convertible securities of the Company shall not be treated as “effected without receipt of consideration by the Company.” Any fractional share resulting from an adjustment pursuant to this Section shall be
rounded down to the nearest whole number, and the Exercise Price shall be rounded up to the nearest whole cent. In no event may the Exercise Price be decreased to an amount less than the par value, if any, of the stock subject to the Option. Such
adjustments shall be determined by the Board, and its determination shall be final, binding and conclusive. 
  

	 	10.	RIGHTS AS A STOCKHOLDER, DIRECTOR, EMPLOYEE OR CONSULTANT.

 The Participant shall have no rights as a stockholder with respect to any shares covered by the Option until the date of the
issuance of the shares for which the Option has been exercised (as evidenced by the appropriate entry on the books of the Company or of a duly authorized transfer agent of the Company). No adjustment shall be made for dividends, distributions or
other rights for which the record date is prior to the date the shares are issued, except as provided in Section 9. If the Participant is an Employee, the Participant understands and acknowledges that, except as otherwise provided in a
separate, written employment agreement between a Participating Company and the Participant, the Participant’s employment is “at will” and is for no specified term. Nothing in this Option Agreement shall confer upon the Participant any
right to continue in the Service of a Participating Company or interfere in any way with any right of the Participating Company Group to terminate the Participant’s Service as a Director, an Employee or Consultant, as the case may be, at any
time. 
  

	 	11.	UNVESTED SHARE REPURCHASE OPTION. 

41.1 Grant of Unvested Share Repurchase Option. In the event the Participant’s Service is terminated for any reason
or no reason, with or without cause, or, if the Participant, the Participant’s legal representative, or other holder of shares acquired pursuant to this Agreement, attempts to sell, exchange, transfer, pledge, or otherwise dispose of (other
than pursuant to an Ownership Change Event) any Unvested Shares, as defined in Section 11.2 below (the “Unvested Shares”), the Company shall have the right to repurchase the Unvested Shares under the terms
and subject to the conditions set forth in this Section 11 (the “Unvested Share Repurchase Option”). 

11.2 Unvested Shares Defined. The “Unvested Shares” shall mean, on any given date,
the number of shares of Stock acquired upon exercise of the Option which exceed the Vested Shares determined as of such date. 
 11.3
Exercise of Unvested Share Repurchase Option. The Company may exercise the Unvested Share Repurchase Option by written notice to the Participant within sixty (60) days after (a) termination of the Participant’s
Service or (b) the Company has received notice of the attempted disposition of Unvested Shares. If the Company fails to give notice within such sixty (60) day period, the Unvested Share Repurchase Option shall terminate unless

  
 9 

 
the Company and the Participant have extended the time for the exercise of the Unvested Share Repurchase Option. Notwithstanding the preceding sentence, the period during which the Company may
exercise the Unvested Share Repurchase Option shall terminate no sooner than the completion of a period of eight (8) months following the date on which the Participant acquired the Unvested Shares upon exercise of the Option. The Unvested Share
Repurchase Option must be exercised, if at all, for all of the Unvested Shares, except as the Company and the Participant otherwise agree. 

11.4 Payment for Shares and Return of Shares to Company. The purchase price per share being repurchased by the Company
(the “Repurchase Price”) shall be an amount equal to the Participant’s original cost per share, as adjusted pursuant to Section 9. The Company shall pay the aggregate Repurchase Price to the
Participant in cash within thirty (30) days after the date of the written notice to the Participant of the Company’s exercise of the Unvested Share Repurchase Option. For purposes of the foregoing, cancellation of any purchase money
indebtedness of the Participant to any Participating Company for the shares shall be treated as payment to the Participant in cash to the extent of the unpaid principal and any accrued interest canceled. The shares being repurchased shall be
delivered to the Company by the Participant at the same time as the delivery of the Repurchase Price to the Participant. 
 11.5
Assignment of Unvested Share Repurchase Option. The Company shall have the right to assign the Unvested Share Repurchase Option at any time, whether or not such option is then exercisable, to one or more persons as may be
selected by the Company. 
 11.6 Ownership Change Event. Upon the occurrence of an Ownership Change Event, any and all
new, substituted or additional securities or other property to which the Participant is entitled by reason of the Participant’s ownership of Unvested Shares shall be immediately subject to the Unvested Share Repurchase Option and included in
the terms “Stock” and “Unvested Shares” for all purposes of the Unvested Share Repurchase Option with the same force and effect as the Unvested Shares immediately prior to the Ownership Change Event. While the aggregate
Repurchase Price shall remain the same after such Ownership Change Event, the Repurchase Price per Unvested Share upon exercise of the Unvested Share Repurchase Option following such Ownership Change Event shall be adjusted as appropriate. 

 

	 	12.	RIGHT OF FIRST REFUSAL. 

12.1 Grant of Right of First Refusal. Except as provided in Section 12.7 and Section 18 below, in the event the
Participant, the Participant’s legal representative, or other holder of shares acquired upon exercise of the Option proposes to sell, exchange, transfer, pledge, or otherwise dispose of any Vested Shares (the “Transfer
Shares”) to any person or entity, including, without limitation, any stockholder of a Participating Company, the Company shall have the right to repurchase the Transfer Shares under the terms and subject to the conditions set
forth in this Section 12 (the “Right of First Refusal”). 
 12.2 Notice of Proposed
Transfer. Prior to any proposed transfer of the Transfer Shares, the Participant shall deliver written notice (the “Transfer Notice”) to the Company describing fully the proposed transfer,
including the number of Transfer Shares, the name and address of the proposed transferee (the “Proposed Transferee”) and, if the transfer is 

  
 10 

 
voluntary, the proposed transfer price, and containing such information necessary to show the bona fide nature of the proposed transfer. In the event of a bona fide gift or involuntary transfer,
the proposed transfer price shall be deemed to be the Fair Market Value of the Transfer Shares, as determined by the Board in good faith. If the Participant proposes to transfer any Transfer Shares to more than one Proposed Transferee, the
Participant shall provide a separate Transfer Notice for the proposed transfer to each Proposed Transferee. The Transfer Notice shall be signed by both the Participant and the Proposed Transferee and must constitute a binding commitment of the
Participant and the Proposed Transferee for the transfer of the Transfer Shares to the Proposed Transferee subject only to the Right of First Refusal. 

12.3 Bona Fide Transfer. If the Company determines that the information provided by the Participant in the Transfer
Notice is insufficient to establish the bona fide nature of a proposed voluntary transfer, the Company shall give the Participant written notice of the Participant’s failure to comply with the procedure described in this Section 12, and
the Participant shall have no right to transfer the Transfer Shares without first complying with the procedure described in this Section 12. The Participant shall not be permitted to transfer the Transfer Shares if the proposed transfer is not
bona fide. 
 12.4 Exercise of Right of First Refusal. If the Company determines the proposed transfer to be bona fide,
the Company shall have the right to purchase all, but not less than all, of the Transfer Shares (except as the Company and the Participant otherwise agree) at the purchase price and on the terms set forth in the Transfer Notice by delivery to the
Participant of a notice of exercise of the Right of First Refusal within thirty (30) days after the date the Transfer Notice is delivered to the Company. The Company’s exercise or failure to exercise the Right of First Refusal with respect
to any proposed transfer described in a Transfer Notice shall not affect the Company’s right to exercise the Right of First Refusal with respect to any proposed transfer described in any other Transfer Notice, whether or not such other Transfer
Notice is issued by the Participant or issued by a person other than the Participant with respect to a proposed transfer to the same Proposed Transferee. If the Company exercises the Right of First Refusal, the Company and the Participant shall
thereupon consummate the sale of the Transfer Shares to the Company on the terms set forth in the Transfer Notice within sixty (60) days after the date the Transfer Notice is delivered to the Company (unless a longer period is offered by the
Proposed Transferee); provided, however, that in the event the Transfer Notice provides for the payment for the Transfer Shares other than in cash, the Company shall have the option of paying for the Transfer Shares by the present value cash
equivalent of the consideration described in the Transfer Notice as reasonably determined by the Company. For purposes of the foregoing, cancellation of any indebtedness of the Participant to any Participating Company shall be treated as payment to
the Participant in cash to the extent of the unpaid principal and any accrued interest canceled. Notwithstanding anything contained in this Section to the contrary, the period during which the Company may exercise the Right of First Refusal and
consummate the purchase of the Transfer Shares from the Participant shall terminate no sooner than the completion of a period of eight (8) months following the date on which the Participant acquired the Transfer Shares upon exercise of the
Option. 
 12.5 Failure to Exercise Right of First Refusal. If the Company fails to exercise the Right of First Refusal
in full (or to such lesser extent as the Company and the Participant otherwise agree) within the period specified in Section 12.4 above, the Participant 

  
 11 

 
may conclude a transfer to the Proposed Transferee of the Transfer Shares on the terms and conditions described in the Transfer Notice, provided such transfer occurs not later than ninety
(90) days following delivery to the Company of the Transfer Notice or, if applicable, following the end of the period described in the last sentence of Section 12.4. The Company shall have the right to demand further assurances from the
Participant and the Proposed Transferee (in a form satisfactory to the Company) that the transfer of the Transfer Shares was actually carried out on the terms and conditions described in the Transfer Notice. No Transfer Shares shall be transferred
on the books of the Company until the Company has received such assurances, if so demanded, and has approved the proposed transfer as bona fide. Any proposed transfer on terms and conditions different from those described in the Transfer Notice, as
well as any subsequent proposed transfer by the Participant, shall again be subject to the Right of First Refusal and shall require compliance by the Participant with the procedure described in this Section 12. 

12.6 Transferees of Transfer Shares. All transferees of the Transfer Shares or any interest therein, other than the
Company, shall be required as a condition of such transfer to agree in writing (in a form satisfactory to the Company) that such transferee shall receive and hold such Transfer Shares or interest therein subject to all of the terms and conditions of
this Option Agreement, including this Section 12 providing for the Right of First Refusal with respect to any subsequent transfer. Any sale or transfer of any shares acquired upon exercise of the Option shall be void unless the provisions of
this Section 12 are met. 
 12.7 Transfers Not Subject to Right of First Refusal. The Right of First Refusal shall
not apply to any transfer or exchange of the shares acquired upon exercise of the Option if such transfer or exchange is in connection with an Ownership Change Event. If the consideration received pursuant to such transfer or exchange consists of
stock of a Participating Company, such consideration shall remain subject to the Right of First Refusal unless the provisions of Section 12.9 below result in a termination of the Right of First Refusal. 

12.8 Assignment of Right of First Refusal. The Company shall have the right to assign the Right of First Refusal at any
time, whether or not there has been an attempted transfer, to one or more persons as may be selected by the Company. 
 12.9 Early
Termination of Right of First Refusal. The other provisions of this Option Agreement notwithstanding, the Right of First Refusal shall terminate and be of no further force and effect upon (a) the occurrence of a Change in
Control, unless the Acquiror assumes the Company’s rights and obligations under the Option or substitutes a substantially equivalent option for the Acquiror’s stock for the Option, or (b) the existence of a public market for the class
of shares subject to the Right of First Refusal. A “public market” shall be deemed to exist if (i) such stock is listed on a national securities exchange (as that term is used in the Exchange Act) or
(ii) such stock is traded on the over-the-counter market and prices therefor are published daily on business days in a recognized financial journal. 

 

	 	13.	STOCK DISTRIBUTIONS SUBJECT TO OPTION AGREEMENT. 

If, from time to time, there is any stock dividend, stock split or other change, as described in Section 9, in the character or amount of
any of the outstanding stock of the corporation the stock of which is subject to the provisions of this Option Agreement, then in such event any and 

  
 12 

 
all new, substituted or additional securities to which the Participant is entitled by reason of the Participant’s ownership of the shares acquired upon exercise of the Option shall be
immediately subject to the Unvested Share Repurchase Option and the Right of First Refusal with the same force and effect as the shares subject to the Unvested Share Repurchase Option and the Right of First Refusal immediately before such event.

  

	 	14.	ESCROW. 

 14.1
Appointment of Agent. To ensure that shares subject to the Unvested Share Repurchase Option will be available for repurchase, the Participant and the Company hereby appoint the Secretary of the Company, or any other person designated by the
Company, as their agent and as attorney-in-fact for the Participant (the “Agent”) to hold any and all Unvested Shares and to sell, assign and transfer to the Company any such Unvested Shares repurchased by the
Company pursuant to the Unvested Share Repurchase Option. The Participant understands that appointment of the Agent is a material inducement to make this Agreement and that such appointment is coupled with an interest and is irrevocable. The Agent
shall not be personally liable for any act the Agent may do or omit to do hereunder as escrow agent, agent for the Company, or attorney in fact for the Participant while acting in good faith and in the exercise of the Agent’s own good judgment,
and any act done or omitted by the Agent pursuant to the advice of the Agent’s own attorneys shall be conclusive evidence of such good faith. The Agent may rely upon any letter, notice or other document executed by any signature purporting to
be genuine and may resign at any time. 
 14.2 Establishment of Escrow. The Participant authorizes the Company to
deposit the Unvested Shares with the Company’s transfer agent to be held in book entry form, as provided by Section 4.5, and the Participant agrees to deliver to and deposit with the Agent each certificate, if any, evidencing the Unvested
Shares and an Assignment Separate from Certificate with respect to such book entry shares and each such certificate duly endorsed (with date and number of shares blank) in the form attached to this Agreement, to be held by the Agent under the terms
and conditions of this Section (the “Escrow”). Upon the occurrence of an Ownership Change Event, a dividend or distribution to the stockholders of the Company paid in shares of Stock or other property (other
than regular, periodic dividends paid on Stock pursuant to the Company’s dividend policy), or any other adjustment upon a change in the capital structure of the Company, as described in Section 9, any and all new, substituted or additional
securities or other property to which the Participant is entitled by reason of his or her ownership of the shares that remain, following such Ownership Change Event, dividend, distribution or change described in Section 9, subject to the
Unvested Share Repurchase Option shall be immediately subject to the Escrow to the same extent as the shares immediately before such event. The Company shall bear the expenses of the Escrow. 

14.3 Delivery of Shares to Participant. The Escrow shall continue with respect to any shares for so long as such shares
remain subject to the Unvested Share Repurchase Option. Upon termination of the Unvested Share Repurchase Option with respect to shares, the Company shall so notify the Agent and direct the Agent to deliver such number of shares to the Participant.
As soon as practicable after receipt of such notice, the Agent shall cause to be delivered to the Participant the shares specified by such notice, and the Escrow shall terminate with respect to such shares. 

14.4 Notices and Payments. In the event the shares and any other property held in escrow are subject to the
Company’s exercise of the Unvested Share Repurchase Option or the Right of First Refusal, the notices required to be given to the Participant shall be given to the Agent, and any payment required to be given to the Participant shall be given to
the Agent. Within thirty (30) days after payment by the Company, the Agent shall deliver the shares and any other property which the Company has purchased to the Company and shall deliver the payment received from the Company to the
Participant. 

  
 13 

	 	15.	NOTICE OF SALES UPON DISQUALIFYING DISPOSITION. 

The Participant shall dispose of the shares acquired pursuant to the Option only in accordance with the provisions of this Option Agreement. In
addition, if the Grant Notice designates this Option as an Incentive Stock Option, the Participant shall (a) promptly notify the Chief Financial Officer of the Company if the Participant disposes of any of the shares acquired pursuant to
the Option within one (1) year after the date the Participant exercises all or part of the Option or within two (2) years after the Date of Grant and (b) provide the Company with a description of the circumstances of such disposition.
Until such time as the Participant disposes of such shares in a manner consistent with the provisions of this Option Agreement, unless otherwise expressly authorized by the Company, the Participant shall hold all shares acquired pursuant to the
Option in the Participant’s name (and not in the name of any nominee) for the one-year period immediately after the exercise of the Option and the two-year period immediately after Date of Grant. At any time during the one-year or two-year
periods set forth above, the Company may place a legend on any certificate representing shares acquired pursuant to the Option requesting the transfer agent for the Company’s stock to notify the Company of any such transfers. The obligation of
the Participant to notify the Company of any such transfer shall continue notwithstanding that a legend has been placed on the certificate pursuant to the preceding sentence. 
  

	 	16.	LEGENDS. 

 The Company
may at any time place legends referencing the Unvested Share Repurchase Option, the Right of First Refusal and any applicable federal, state or foreign securities law restrictions on all certificates representing shares of stock subject to the
provisions of this Option Agreement. The Participant shall, at the request of the Company, promptly present to the Company any and all certificates representing shares acquired pursuant to the Option in the possession of the Participant in order to
carry out the provisions of this Section. Unless otherwise specified by the Company, legends placed on such certificates may include, but shall not be limited to, the following: 

16.1 “THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE
SOLD, TRANSFERRED, ASSIGNED OR HYPOTHECATED UNLESS THERE IS AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH ACT COVERING SUCH SECURITIES, THE SALE IS MADE IN ACCORDANCE WITH RULE 144 OR RULE 701 UNDER THE ACT, OR THE COMPANY RECEIVES AN OPINION
OF COUNSEL REASONABLY SATISFACTORY TO THE COMPANY, STATING THAT SUCH SALE, TRANSFER, ASSIGNMENT OR HYPOTHECATION IS EXEMPT FROM THE REGISTRATION AND PROSPECTUS DELIVERY REQUIREMENTS OF SUCH ACT.” 

  
 14 

 16.2 “THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN RESTRICTIONS ON
TRANSFER AND REPURCHASE OPTIONS IN FAVOR OF THE CORPORATION OR ITS ASSIGNEE SET FORTH IN AN AGREEMENT BETWEEN THE CORPORATION AND THE REGISTERED HOLDER, OR SUCH HOLDER’S PREDECESSOR IN INTEREST, A COPY OF WHICH IS ON FILE AT THE PRINCIPAL
OFFICE OF THIS CORPORATION.” 
 16.3 “THE SHARES EVIDENCED BY THIS CERTIFICATE WERE ISSUED BY THE CORPORATION TO THE REGISTERED
HOLDER UPON EXERCISE OF AN INCENTIVE STOCK OPTION AS DEFINED IN SECTION 422 OF THE INTERNAL REVENUE CODE OF 1986, AS AMENDED (“ISO”). IN ORDER TO OBTAIN THE PREFERENTIAL TAX TREATMENT AFFORDED TO ISOs, THE SHARES SHOULD NOT BE
TRANSFERRED PRIOR TO [INSERT DISQUALIFYING DISPOSITION DATE HERE]. SHOULD THE REGISTERED HOLDER ELECT TO TRANSFER ANY OF THE SHARES PRIOR TO THIS DATE AND FOREGO ISO TAX TREATMENT, THE TRANSFER AGENT FOR THE SHARES SHALL NOTIFY THE
CORPORATION IMMEDIATELY. THE REGISTERED HOLDER SHALL HOLD ALL SHARES PURCHASED UNDER THE INCENTIVE STOCK OPTION IN THE REGISTERED HOLDER’S NAME (AND NOT IN THE NAME OF ANY NOMINEE) PRIOR TO THIS DATE OR UNTIL TRANSFERRED AS DESCRIBED
ABOVE.” 
  

	 	17.	LOCK-UP AGREEMENT. 

The Participant hereby agrees that in the event of any underwritten public offering of stock, including an initial public offering of stock,
made by the Company pursuant to an effective registration statement filed under the Securities Act, the Participant shall not offer, sell, contract to sell, pledge, hypothecate, grant any option to purchase or make any short sale of, or otherwise
dispose of any shares of stock of the Company or any rights to acquire stock of the Company for such period of time from and after the effective date of such registration statement as may be established by the underwriter for such public offering;
provided, however, that such period of time shall not exceed one hundred eighty (180) days from the effective date of the registration statement to be filed in connection with such public offering; provided, further, however, that such one
hundred eighty (180) day period may be extended for an additional period, not to exceed twenty (20) days, upon the request of the Company or the underwriter to accommodate regulatory restrictions on (i) the publication or
other distribution of research reports and (ii) analyst recommendations and opinions, including but not limited to, the restrictions contained in NASD Rule 2711(f)(4) or NYSE Rule 472(f)(4), or any successor provisions or amendments thereto).
The foregoing limitation shall not apply to shares registered in the public offering under the Securities Act. The Participant hereby agrees to enter into any agreement reasonably required by the underwriters to implement the foregoing within a
reasonable timeframe if so requested by the Company. 

  
 15 

	 	18.	RESTRICTIONS ON TRANSFER OF SHARES. 

No shares acquired upon exercise of the Option may be sold, exchanged, transferred (including, without limitation, any transfer to a nominee or
agent of the Participant), assigned, pledged, hypothecated or otherwise disposed of, including by operation of law in any manner which violates any of the provisions of this Option Agreement, and, except pursuant to an Ownership Change Event, until
the date on which such shares become Vested Shares, and any such attempted disposition shall be void. The Company shall not be required (a) to transfer on its books any shares which will have been transferred in violation of any of the
provisions set forth in this Option Agreement or (b) to treat as owner of such shares or to accord the right to vote as such owner or to pay dividends to any transferee to whom such shares will have been so transferred. 

 

	 	19.	MISCELLANEOUS PROVISIONS. 

19.1 Termination or Amendment. The Board may terminate or amend the Plan or the Option at any time; provided, however, that except as
provided in Section 8 in connection with a Change in Control, no such termination or amendment may adversely affect the Option or any unexercised portion hereof without the consent of the Participant unless such termination or amendment is
necessary to comply with any applicable law or government regulation, including, but not limited to Section 409A of the Code. No amendment or addition to this Option Agreement shall be effective unless in writing. 

19.2 Compliance with Section 409A. The Company intends that income realized by the Participant pursuant to the Plan and this
Option Agreement will not be subject to taxation under Section 409A of the Code. The provisions of the Plan and this Option Agreement shall be interpreted and construed in favor of satisfying any applicable requirements of Section 409A of
the Code. The Company, in its reasonable discretion, may amend (including retroactively) the Plan and this Agreement in order to conform to the applicable requirements of Section 409A of the Code, including amendments to facilitate the
Participant’s ability to avoid taxation under Section 409A of the Code. However, the preceding provisions shall not be construed as a guarantee by the Company of any particular tax result for income realized by the Participant pursuant
to the Plan or this Option Agreement. In any event, and except for the responsibilities of the Company set forth in Section 4.4, no Participating Company shall be responsible for the payment of any applicable taxes incurred by the
Participant on income realized by the Participant pursuant to the Plan or this Option Agreement. 
 19.3 Further Instruments. The
parties hereto agree to execute such further instruments and to take such further action as may reasonably be necessary to carry out the intent of this Option Agreement. 

19.4 Binding Effect. This Option Agreement shall inure to the benefit of the successors and assigns of the Company and, subject to the
restrictions on transfer set forth herein, be binding upon the Participant and the Participant’s heirs, executors, administrators, successors and assigns. 

  
 16 

 19.5 Delivery of Documents and Notices. Any document relating to participation in the
Plan, or any notice required or permitted hereunder shall be given in writing and shall be deemed effectively given (except to the extent that this Option Agreement provides for effectiveness only upon actual receipt of such notice) upon personal
delivery, electronic delivery at the e-mail address, if any, provided for the Participant by a Participating Company, or, upon deposit in the U.S. Post Office or foreign postal service, by registered or certified mail, or with a nationally
recognized overnight courier service, with postage and fees prepaid, addressed to the other party at the address of such party set forth in the Grant Notice or at such other address as such party may designate in writing from time to time to the
other party. 
 (a) Description of Electronic Delivery. The Plan documents, which may include but do not necessarily
include: the Plan, the Grant Notice, this Option Agreement, and any reports of the Company provided generally to the Company’s stockholders, may be delivered to the Participant electronically. In addition, if permitted by the Company, the
Participant may deliver electronically the Grant Notice and Exercise Notice called for by Section 4.2 to the Company or to such third party involved in administering the Plan as the Company may designate from time to time. Such means of
electronic delivery may include but do not necessarily include the delivery of a link to a Company intranet or the Internet site of a third party involved in administering the Plan, the delivery of the document via e-mail or such other means of
electronic delivery specified by the Company. 
 (b) Consent to Electronic Delivery. The Participant acknowledges that the
Participant has read Section 19.5(a) of this Option Agreement and consents to the electronic delivery of the Plan documents and, if permitted by the Company, the delivery of the Grant Notice, Exercise Notice and notices in connection with the
Escrow, as described in Section 19.5(a). The Participant acknowledges that he or she may receive from the Company a paper copy of any documents delivered electronically at no cost to the Participant by contacting the Company by telephone or in
writing. The Participant further acknowledges that the Participant will be provided with a paper copy of any documents if the attempted electronic delivery of such documents fails. Similarly, the Participant understands that the Participant must
provide the Company or any designated third party administrator with a paper copy of any documents if the attempted electronic delivery of such documents fails. The Participant may revoke his or her consent to the electronic delivery of documents
described in Section 19.5(a) or may change the electronic mail address to which such documents are to be delivered (if Participant has provided an electronic mail address) at any time by notifying the Company of such revoked consent or revised
e-mail address by telephone, postal service or electronic mail. Finally, the Participant understands that he or she is not required to consent to electronic delivery of documents described in Section 19.5(a). 

19.6 Integrated Agreement. The Grant Notice, this Option Agreement and the Plan, together with any employment, service or other
agreement with the Participant and a Participating Company referring to the Option, shall constitute the entire understanding and agreement of the Participant and the Participating Company Group with respect to the subject matter contained herein or
therein and supersede any prior agreements, understandings, restrictions, representations, or warranties among the Participant and the Participating Company Group with respect to such subject matter. To the extent contemplated herein or therein, the
provisions of the Grant Notice, the Option Agreement and the Plan shall survive any exercise of the Option and shall remain in full force and effect. 

  
 17 

 19.7 Applicable Law. This Option Agreement shall be governed by the laws of the State of
Delaware as such laws are applied to agreements between Delaware residents entered into and to be performed entirely within the State of Delaware. 

19.8 Counterparts. The Grant Notice may be executed in counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument. 

  
 18 

									
	Incentive Stock Option	 		  	Participant:	 	  

	Nonstatutory Stock Option	 		  		 		 	
		 		  		 	Date:	 	  

 STOCK OPTION EXERCISE NOTICE 

(Immediately Exercisable) 
 Xtera
Communications, Inc. 
 Attention: Chief Financial Officer 

Ladies and Gentlemen: 
 1. Option.
I was granted an option (the “Option”) to purchase shares of the common stock (the “Shares”) of Xtera Communications, Inc. (the
“Company”) pursuant to the Company’s 2011 Stock Plan (the “Plan”), my Notice of Grant of Stock Option (the “Grant Notice”) and my
Stock Option Agreement (the “Option Agreement”) as follows: 
  

			
	Date of Grant:	  	
		
	Number of Option Shares:	  	
		
	Exercise Price per Share:	  	$            

 2. Exercise of Option. I hereby elect to exercise the Option to purchase the following
number of Shares, in accordance with the Grant Notice and the Option Agreement: 
  

			
	Vested Shares:	  	
		
	Unvested Shares:	  	
		
	Total Shares Purchased:	  	
		
	Total Exercise Price (Total Shares X Price per Share)	  	$            

 3. Payments. I enclose payment in full of the total exercise price for the Shares in the
following form(s), as authorized by my Option Agreement: 
  

			
	Cash:	  	$            
		
	Check:	  	$            
		
	Stock Tender Exercise:	  	Contact Plan Administrator
		
	Cashless Exercise:	  	Contact Plan Administrator
		
	Net Exercise:	  	Contact Plan Administrator

  
 1 

 4. Tax Withholding. I authorize payroll withholding and otherwise will make
adequate provision for the federal, state, local and foreign tax withholding obligations of the Company, if any, in connection with the Option. If I am exercising a Nonstatutory Stock Option, I enclose payment in full of my withholding taxes, if
any, as follows: 
 (Contact Plan Administrator for amount of tax due.) 

 

			
	Cash:	  	$            
		
	Check:	  	$            

 5. Participant Information. 

 

			
	My address is:	 	  

		
		 	  

 
			
		
	My Social Security Number is:	 	  

 6. Notice of Disqualifying Disposition. If the Option is an Incentive Stock Option, I
agree that I will promptly notify the Chief Financial Officer of the Company if I transfer any of the Shares within one (1) year from the date I exercise all or part of the Option or within two (2) years of the Date of Grant. 

7. Binding Effect. I agree that the Shares are being acquired in accordance with and subject to the terms, provisions and
conditions of the Grant Notice, the Option Agreement, including the Unvested Share Repurchase Option and the Right of First Refusal set forth therein, and the Plan, to all of which I hereby expressly assent. This Agreement shall inure to the benefit
of and be binding upon my heirs, executors, administrators, successors and assigns. If required by the Company, I agree to deposit the certificate(s) evidencing the Shares, along with a blank stock assignment separate from certificate executed by
me, with an escrow agent designated by the Company, to be held pursuant to the escrow provisions contained in the Option Agreement. 
 8.
Transfer. I understand and acknowledge that the Shares have not been registered under the Securities Act of 1933, as amended (the “Securities Act”), and that consequently the Shares must be held
indefinitely unless they are subsequently registered under the Securities Act, an exemption from such registration is available, or they are sold in accordance with Rule 144 or Rule 701 under the Securities Act. I further understand and
acknowledge that the Company is under no obligation to register the Shares. I understand that the certificate or certificates evidencing the Shares will be imprinted with legends which prohibit the transfer of the Shares unless they are registered
or such registration is not required in the opinion of legal counsel satisfactory to the Company. 
 9. Election Under
Section 83(b) of the Code. I understand and acknowledge that if I am exercising the Option to purchase Unvested Shares (i.e., shares that remain subject to the Company’s Unvested Share Repurchase Option), that I should consult with
my tax advisor regarding the advisability of filing with the Internal Revenue Service an election under Section 83(b) of the Code, which must be filed, if at all, no later than thirty (30) days after the date on which I exercise the
Option. I acknowledge that I have been advised to consult with a tax advisor prior to the exercise of the Option regarding the tax consequences to me of exercising the Option and filing or not filing an election under Section 83(b). AN ELECTION
UNDER SECTION 83(b) MUST BE FILED, IF AT ALL, WITHIN 30 DAYS AFTER THE DATE ON WHICH I PURCHASE SHARES. THIS TIME PERIOD CANNOT BE EXTENDED. I ACKNOWLEDGE THAT TIMELY FILING OF A SECTION 83(b) ELECTION, IF APPROPRIATE, IS MY SOLE
RESPONSIBILITY, EVEN IF I REQUEST THE COMPANY OR ITS REPRESENTATIVES TO FILE SUCH ELECTION ON MY BEHALF. 
 I am aware that Rule 144
under the Securities Act, which permits limited public resale of securities acquired in a nonpublic offering, is not currently available with respect to the Shares and, in any event, is available only if certain conditions are satisfied. I
understand that any sale of the Shares that might be made in reliance upon Rule 144 may only be made in limited amounts in accordance with the terms and conditions of such rule and that a copy of Rule 144 will be delivered to me upon
request. 

  
 2 

 I understand that I am purchasing the Shares pursuant to the terms of the Plan, the Grant Notice
and my Option Agreement, copies of which I have received and carefully read and understand. 
  

	
	Very truly yours,
	
	  

	(Signature)

  

			
	Receipt of the above is hereby acknowledged.
	
	Xtera Communications, Inc.
		
	By:	 	  

		
	Title:	 	  

		
	Dated:	 	  

  
 3 

 ASSIGNMENT SEPARATE FROM CERTIFICATE 

FOR VALUE RECEIVED the undersigned does hereby sell, assign and transfer unto
                                         
                                       
(                ) shares of the Capital Stock of Xtera Communications, Inc. standing in the undersigned’s name on the books of said corporation represented by
Certificate No.              herewith and does hereby irrevocably constitute and appoint
                                         Attorney
to transfer the said stock on the books of said corporation with full power of substitution in the premises. 
  

			
	Dated:	 	  

  

	
	  

	Signature
	
	  

	Print Name

 Instructions: Please do not fill in any blanks other than the signature line. The purpose of this assignment is
to enable the Company to exercise its Unvested Share Repurchase Option set forth in the Stock Option Agreement without requiring additional signatures on the part of the Participant. 

 Xtera Communications, Inc. 

2011 Stock Plan 
 NOTICE OF STOCK
OPTION GRANT 
 Xtera Communications, Inc. (the “Company”) pursuant to its 2011 Stock Plan (the “Plan”), hereby grants to
Optionee an option to purchase the number of shares of the Company’s COMMON Stock set forth below. This option is subject to all of the terms and conditions as set forth herein and in the Option Plan, the Stock Option Agreement, and any
ancillary documents, all of which are delivered herewith and incorporated herein in their entirety. 
  

					
	Name of Optionee:	 	  
	 	
			
	Optionee Address:	 	  
	 	
			
	Grant ID:	 	  
	 	
			
	Grant Date:	 	  
	 	
			
	Vesting Start Date:	 	  
	 	
			
	Total Number of Shares Granted:	 	  
	 	
			
	Exercise Price Per Share:	 	  
	 	
			
	Total Exercise Price:	 	  
	 	
			
	Expiration Date:	 	  
	 	

  

			
	Type of Option Grant:	  	 ̈ Incentive Stock Option (ISO)      ̈ Nonstatutory Stock Option (NSO)
		
	Vesting Schedule:	  	                                      
                                  
		
	Exercise Schedule:	  	 ̈ Early Exercise Permitted      ̈ Same as Vesting Schedule
		
	Termination Period:	  	The vested shares of this Option may only be exercised after termination of your services for the Company to the extent provided in the Stock Option Agreement (but in no event later than the Expiration Date). Optionee is responsible
for keeping track of these exercise periods following termination for any reason of his or her service relationship with the Company. The Company will not provide further notice of such periods.
		
	Transferability:	  	This Option may not be transferred.

 By clicking the “ACCEPT” button below, you and the Company agree that this option is granted under and
governed by the terms and conditions of the Option Plan (the “Plan”), the Stock Option Agreement, and any ancillary documents, all of which you can access through a link from this Notice of Grant and made a part of this document. Before
you may electronically sign this Notice of Grant, you must click on and review the linked Option Plan, Stock Option Agreement, and any ancillary documents. PLEASE BE SURE TO READ THE STOCK OPTION AGREEMENT, WHICH CONTAINS THE SPECIFIC TERMS AND
CONDITIONS OF THIS OPTION, INCLUDING INFORMATION CONCERNING CANCELLATION AND TERMINATION OF THIS OPTION. 

  
 1 

 By clicking the “ACCEPT” button below, you agree to the following: 

I acknowledge and agree that: 
 (a) I have been able to access
and view the Notice of Grant, the Option Plan, the Stock Option Agreement, and any ancillary documents and understand that all rights and obligations with respect to these Shares are set forth in the Notice of Grant, the Option Plan, the Stock
Option Agreement, and any ancillary documents; 
 (b) I agree to all terms and conditions contained in the Notice of Grant, the Option Plan, the Stock
Option Agreement, and any ancillary documents; 
 (c) as of the date hereof, the Notice of Grant, the Option Plan, the Stock Option Agreement, and any
ancillary documents set forth the entire understanding between the Company and me regarding the acquisition of the Shares and supersedes all prior oral and written agreements with respect thereto; and 

(d) my rights to any Shares underlying the Option will be earned only as I provide services to the Company over time, that the grant of the Option is not as
consideration for services I rendered to the Company prior to my Vesting Start Date, and that nothing in this Notice or the attached documents confers upon me any right to continue my services to the Company for any period of time, nor does it
interfere in any way with my right or the Company’s right to terminate that relationship at any time, for any reason, with or without cause. 
 It is
recommended that you print a copy of your Grant Notice and all documents linked to this page for your records. 
  

	
	Xtera Communications, Inc.
	
	  

	Paul Colan
	CFO

  
 2

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