<PAGE>

                                                                  EXHIBIT 4.02

                         Registration rights agreement

     This Registration Rights Agreement (this "Agreement") is entered into as of
February 12, 2001 (the "Agreement Date") and is contingent and effective upon
the Closing Date (as defined in the Purchase Agreement, defined below), by and
between ONI Systems Corp., a Delaware corporation (the "Company") and Finisar
Corporation ("Finisar"), a Delaware corporation.

                                   Recitals

          A.   This Agreement is entered into pursuant to and concurrently with
the execution of that certain Asset Acquisition Agreement dated as of February
12, 2001 (the "Purchase Agreement") by and between the Company and Finisar,
under which the Company shall issue to Finisar shares of the Company's Common
Stock, par value $0.0001 per share (the "Shares").

          B.   As an inducement for Finisar to enter into the Purchase
Agreement, the Company desires to grant the registration rights to Finisar as
contained herein.

     Now, therefore, in consideration of the foregoing and the mutual promises,
covenants and conditions contained herein, the parties hereby agree as follows:

                                   ARTICLE 1
                              Certain Definitions

     As used in this Agreement, the following terms will have the meanings set
forth below:

     1.1  Certain Definitions.  For purposes of Article 2:
          -------------------

          (a)  Commission or SEC.  The terms "Commission" and "SEC" means the
               -----------------
Securities and Exchange Commission or any other federal agency at the time
administering the Securities Act (as defined below).

          (b)  Existing Rights Agreement.  The term "Existing Rights Agreement"
               -------------------------
means that certain Investors' Rights Agreement by and among the Company and
certain investors and other parties, dated as of May 9, 2000.

          (c)  Form S-3.  The term "Form S-3" means a registration statement
               --------
filed under Form S-3 under the Securities Act, as such is in effect on the date
hereof, or any successor form of registration statement under the Securities Act
subsequently adopted by the SEC which permits inclusion or incorporation of a
substantial amount of information by reference to other documents filed by the
Company with the SEC.

          (d)  Holder.  The term "Holder" means Finisar or any assignee of
               ------
record of any Registrable Securities to whom rights under this Agreement have
been duly assigned in accordance with the provisions of this Agreement.
<PAGE>

          (e)  Registration.  The terms "register," "registered" and
               ------------
"registration" refer to a registration effected by preparing and filing a
registration statement in compliance with the Securities Act (and any post-
effective amendments filed or required to be filed), and the declaration or
ordering of effectiveness of such registration statement.

          (f)  Registration Expenses.  The term "Registration Expenses" means
               ---------------------
all expenses incurred by the Company in complying with Sections 2.1 and 2.2,
including, without limitation, all registration, qualification and filing fees,
printing expenses, escrow fees, fees and disbursements of counsel for the
Company, blue sky fees and expenses, and the expense of any special audits
incident to or required by any such registration. Registration Expenses shall
not include selling commissions, discounts or other compensation paid to
underwriters or other agents or brokers to effect the sale.

          (g)  Registrable Securities.  The term "Registrable Securities" means
               ----------------------
(i) the Shares that are issued to Finisar pursuant to the Purchase Agreement,
and (ii) any shares of Common Stock of the Company that may be issued as a
dividend or other distribution (including shares of Common Stock of the Company
issued in a subdivision and split of the Company's outstanding Common Stock)
with respect to, or in exchange for, or in replacement of, shares of Common
Stock of the Company described in clauses (i) of this Section 1.1(g) or in this
clause (ii); excluding in all cases, however, from the definition of
             ---------
"Registrable Securities" any such shares that are: (v) registered under the
Securities Act other than pursuant to a registration statement filed pursuant to
this Agreement; (w) sold by a person in a transaction in which rights under this
Agreement with respect to such shares are not assigned in accordance with the
terms of this Agreement; (x) sold pursuant to a registration statement filed
pursuant to this Agreement; or (y) sold pursuant to Rule 144 promulgated under
the Securities Act or otherwise sold to the public. Except as provided in clause
(ii) of the first sentence of this Section 1.1(g), without limitation, the term
"Registrable Securities" does not include any shares of Common Stock the Company
that were not issued in connection with the Purchase Agreement.

          (h)  Securities Act.  The term "Securities Act" means the Securities
               --------------
Act of 1933, as amended, or any similar federal statute and the rules and
regulations of the Commission thereunder, as shall be in effect at the time.

  Other capitalized terms defined elsewhere in this Agreement and not defined in
this Article 1 will have the meanings assigned to such terms in this Agreement.
Capitalized terms not defined herein shall have the meanings assigned to such
terms in the Purchase Agreement.

                                       2
<PAGE>

                                   ARTICLE 2
                              Registration Rights

          2.1  Company Registration.
               --------------------

               (a)  Notice of Registration.  If at any time or from time to
                    ----------------------
               time, the Company shall determine to register in an underwritten
               offering any of its securities, either for its own account or the
               account of a security holder or holders exercising their
               respective demand registration rights pursuant to Section 2.2 of
               the Existing Rights Agreement, other than (i) a registration
               relating solely to employee benefit plans, or (ii) a registration
               relating solely to a Commission Rule 145 transaction, the Company
               shall:

                    (x)  promptly give to Holder written notice thereof; and

                    (y)  include in such registration (and any related
                         qualification under blue sky laws or other compliance),
                         and in any underwriting involved therein, all the
                         Registrable Securities specified in a written request
                         by Holder received by the Company within 15 days after
                         the Company mails such written notice, subject to the
                         provisions below.

               (b)  Underwriting. The right of Holder to registration pursuant
                    ------------
                    to Section 2.1 shall be conditioned upon the participation
                    by Holder in such underwriting and the inclusion of the
                    Registrable Securities of Holder in the underwriting to the
                    extent provided herein. If Holder wishes to distribute its
                    securities through such underwriting, it shall (together
                    with the Company and any other stockholders of the Company
                    distributing their securities through such underwriting)
                    enter into an underwriting agreement in customary form with
                    the managing underwriter selected for such underwriting by
                    the Company. Notwithstanding any other provision of this
                    Section 2.1, if the managing underwriter determines that
                    marketing factors require a limitation of the number of
                    shares to be underwritten, the managing underwriter may
                    limit the Registrable Securities held by Holder to be
                    included in such registration. The Company shall so advise
                    Holder and the other stockholders distributing their
                    securities through such underwriting, and the number of
                    shares of Registrable Securities and other securities that
                    may be included in the registration and underwriting shall
                    be allocated among Holder and the other stockholders
                    distributing their securities through such underwriting in
                    proportion, as nearly as practicable, to the respective
                    amounts of securities entitled to inclusion (determined
                    without regard to any requirement of a request to be
                    included in such registration) in such registration held by
                    all such stockholders at the time of filing the registration
                    statement, provided that no such inclusion of Registrable
                    Securities and other securities by the underwriter may
                    reduce the securities being offered by the Company for its
                    own account or for the account of holders exercising
                    registration rights under Section 2.2 of the Existing Rights
                    Agreement. To facilitate the allocation of shares in
                    accordance with the above provisions, the Company may round
                    the number of shares allocated to Holder to the nearest 100
                    shares. If Holder disapproves of the terms of any such
                    underwriting, it may elect to withdraw therefrom by written
                    notice to the Company and the managing underwriter. Any
                    securities excluded or withdrawn from such underwriting
                    shall be withdrawn from such registration, and shall not be
                    transferred in a public

                                       3

<PAGE>

distribution prior to 180 days after the effective date of the registration
statement relating thereto, or such other shorter period of time as the
underwriters may require.

               (c)  Right to Terminate Registration.  The Company shall have the
                    -------------------------------
right to terminate or withdraw any registration initiated by it under this
Section 2.1 prior to the effectiveness of such registration whether or not any
Holder has elected to include securities in such registration.

          2.2  Form S-3 Registration.  At any time after June 1, 2001, in case
               ---------------------
the Company shall receive from Holder a written request that the Company effect
a registration on Form S-3 and any related qualification or compliance with
respect to an amount of the Registrable Securities owned by Holder or holders
under the Existing Rights Agreement for which the anticipated aggregate offering
price would be at least $1,000,000, the Company shall:

          (a)  promptly give written notice of the proposed registration, and
any related qualification or compliance to Holder and all other stockholders of
the Company with registration rights; and

          (b)  as soon as practicable, effect such registration and all such
qualifications and compliances as may be so requested and as would permit or
facilitate the sale and distribution of all or such portion of Holder's
Registrable Securities as are specified in such request, together with all or
such portion of the securities of any stockholders of the Company with
registration rights joining in such request as are specified in a written
request given within 15 days after receipt of such written notice from the
Company; provided, however, that the Company shall not be obligated to effect
any such registration, qualification, or compliance pursuant to this Section
2.2: (1) if Form S-3 is not available for such offering by the Holder; (2) if
the Company shall furnish to Holder a certificate signed by the president of the
Company stating that in the good faith judgment of the Board, it would be
seriously detrimental to the Company and its stockholders for such Form S-3
Registration to be effected at such time, in which event the Company shall have
the right to defer the filing of the Form S-3 registration statement for a
period of not more than 120 days after receipt of the initiating request of
Holder or such other holders under this Section 2.2; provided, however, that the
Company shall not utilize this right more than once in any twelve month period;
(3) if the Company has, within the six (6) month period preceding the date of
such request, already effected a registration in which Holder's Registrable
Securities were included or in which the securities of holders under the
Existing Rights Agreement were included and Holder was afforded the opportunity
to have its Registrable Securities included in such registration statement; (4)
if the Company has already effected two registrations on Form S-3 for Holder
pursuant to this Section 2.2(b); or (5) in any jurisdiction in which the Company
would be required to execute a general consent to service of process in
effecting such registration, qualification or compliance unless the Company is
already subject to service in such jurisdiction and except as may be required by
the Securities Act.

          Subject to the foregoing, the Company shall effect such registration,
qualification, or compliance (including, without limitation, the execution of an
undertaking to file post-effective amendments, appropriate qualification under
applicable blue sky or other state

                                       4
<PAGE>

securities laws and appropriate compliance with applicable regulations issued
under the Securities Act and any other governmental requirements or regulations)
covering the Registrable Securities and other securities so requested to be
registered as soon as practicable after receipt of the request of Holder.

          If the registration to be effected pursuant to this Section 2.2 is to
be an underwritten public offering, it shall be managed by an underwriter or
underwriters selected by the Company reasonably acceptable Holder.  In such
event, the right of Holder to registration pursuant to Section 2.2 shall be
conditioned upon the participation by Holder in such underwriting and the
inclusion of the Registrable Securities of Holder in the underwriting to the
extent provided herein.  If the managing underwriter so selected determines that
marketing factors require a limitation of the number of shares to be
underwritten, the managing underwriter may limit the Registrable Securities held
by Holder to be included in such registration.  The Company shall so advise
Holder, and the number of shares of Registrable Securities that may be included
in the registration shall be allocated among Holder and other stockholders of
the Company with registration rights in proportion to the respective amounts of
Registrable Securities which would be held by each of such stockholders at the
time of filing of the registration statement.  Any Registrable Securities that
are so excluded from the underwriting shall be excluded from the registration.

          2.3  Expenses of Registration.  All Registration Expenses incurred in
               ------------------------
connection with the registration, qualification or compliance pursuant to
Sections 2.1 and 2.2 shall be borne by the Company.

          2.4  Letter or Opinion of Counsel in Lieu of Registration.  If in the
               ----------------------------------------------------
opinion of counsel for the Company concurred in by counsel for Holder (which
concurrence shall not be unreasonably withheld), no registration under the
Securities Act is required in connection with the disposition of the Registrable
Securities covered by any request made under Sections 2.1 or 2.2 in the manner
in which they propose to dispose of the Registrable Securities included in such
request, the Company need not comply with such request or requests; provided,
however, that the Company shall not be so relieved of its obligations under
Sections 2.1 and 2.2 unless such opinion of counsel for the Company shall have
been mailed by the Company to Holder within fifteen (15) days after the
Company's receipt of Holder's request or requests; and provided, further, that
if counsel for the Company has opined that no registration is required in
connection with any such disposition, such counsel shall further opine as to
whether the removal of any legend from certificates representing all shares to
which such opinion refers is permissible, and, if so, the Company shall remove
from such certificates all legends no longer required thereon and shall rescind
any stop-transfer instructions previously communicated to its transfer agent
relating to such shares.

          2.5  Registration Procedures.  Subject to the conditions and
               -----------------------
procedures set forth below in Section 2.6, if and whenever the Company is
required by the provisions of this Article 2 effect promptly the registration of
Registrable Securities held by Holder, the Company shall:

                                       5
<PAGE>

          (a)  Prepare and file with the SEC a registration statement with
respect to such Registrable Securities and use its most diligent efforts to
cause such registration statement to become and remain effective as provided
herein.

          (b)  Prepare and file with the SEC such amendments and supplements to
such registration statement and the prospectus used in connection therewith as
may be necessary to keep such registration statement effective and current and
to comply with the provisions of the Securities Act with respect to the sale or
other disposition of all Registrable Securities covered by such registration
statement, including such amendments and supplements as may be necessary to
reflect the intended method of disposition of the prospective seller or sellers
of such Registrable Securities, but for no longer than one hundred twenty (120)
days subsequent to the effective date of such registration in the case of a
registration statement on Form S-1 (or any similar form of registration
statement required to set forth substantially identical information) and for no
longer than ninety (90) days in the case of a registration statement on Form S-3
(in either case, the "Effectiveness Period").

          (c)  Furnish to Holder such number of copies of a prospectus,
including a preliminary prospectus, in conformity with the requirements of the
Securities Act, and such other documents, as Holder may reasonably request in
order to facilitate the public sale or other disposition of the Registrable
Securities of Holder.

          2.6  Selling Procedures.  Any sale of Registrable Securities by Holder
               ---------------------
pursuant to Section 2.2 hereof shall be subject to the following conditions and
procedures:

          (a)  Holder shall provide written notice ("Stockholder Notice") to the
Company no less than three (3) business days prior to Holder's intended sale.
Within two (2) days of receipt of the Stockholder Notice, the Company will
inform Holder in writing if the registration statement and final prospectus then
on file with the SEC is current and otherwise complies with the Securities Act
such that sales may be made thereunder.  After receipt of notice from the
Company that the registration statement is current and complies with the
Securities Act, Holder shall then have ten (10) business days after the date of
the intended sale, as specified in the Stockholder Notice, to sell the
Registrable Securities proposed to be sold.  After such ten (10) day period,
Holder shall once again comply with the procedures set forth in this Section 2.6
prior to any further sales.

          (b)  If the Company informs Holder that the registration statement or
final prospectus then on file with the SEC is not current or otherwise does not
comply with the Securities Act, the Company shall use its most diligent efforts
to provide to Holder a current prospectus that complies with the Securities Act
on or before the date of the intended sale of the Registrable Securities as
disclosed in the Stockholder's Notice; provided however, that if the Board of
Directors of the Company, acting in good faith, determines that there exists
material nonpublic information about the Company that the Board does not wish to
disclose in a registration statement (due to the fact that such disclosure may
not be in the best interest of the Company's stockholders) which information
would otherwise be required by the Securities Act to be disclosed in the
registration statement to be filed pursuant to Section 2.2, the Company

                                       6
<PAGE>

shall have the right, no more than one (1) time during any Effectiveness Period,
to delay the preparation of a current prospectus that complies with the
Securities Act for up to thirty (30) days without explanation to Holder.

          2.7  Indemnification.  In the event any of the Registrable Securities
               ---------------
are included in a registration statement under this Article 2:

          (a)  The Company will indemnify Holder, each of its officers and
directors and partners and Holder's separate legal counsel and independent
accountants, and each person controlling Holder within the meaning of Section 15
of the Securities Act, and each underwriter, if any, and each person who
controls any underwriter within the meaning of Section 15 of the Securities Act,
against all expenses, claims, losses, damages or liabilities (or actions in
respect thereof), including any of the foregoing incurred in settlement of any
litigation, commenced or threatened, arising out of or based on any untrue
statement (or alleged untrue statement) of a material fact contained in any
registration statement, prospectus, offering circular or other document, or any
amendment or supplement thereto, incident to any such registration,
qualification or compliance, or based on any omission (or alleged omission) to
state therein a material fact required to be stated therein or necessary to make
the statements therein, in light of the circumstances in which they were made,
not misleading, or any violation by the Company of any rule or regulation
promulgated under the Securities Act applicable to the Company in connection
with any such registration, qualification or compliance, and the Company will
reimburse Holder, each of its officers and directors and partners and Holder's
separate legal counsel and independent accountants and each person controlling
Holder, each such underwriter and each person who controls any such underwriter,
for any legal and any other expenses reasonably incurred in connection with
investigating, preparing or defending any such claim, loss, damage, liability or
action, provided that the Company will not be liable in any such case to the
extent that any such claim, loss, damage, liability or expense arises out of or
is based on any untrue statement or omission or alleged untrue statement or
omission, made in reliance upon and in conformity with written information
furnished to the Company by an instrument duly executed by Holder or underwriter
and stated to be specifically for use therein.

          (b)  Holder will, if Registrable Securities held by Holder are
included in the securities as to which such registration, qualification or
compliance is being effected, indemnify the Company, each of its directors and
officers and its legal counsel and independent accountants, each underwriter, if
any, of the Company's securities covered by such a registration statement, each
person who controls the Company or such underwriter within the meaning of
Section 15 of the Securities Act, and each other stockholder of the Company
distributing its securities through such registration, each of its officers and
directors and each person controlling such stockholders within the meaning of
Section 15 of the Securities Act, against all claims, losses, damages and
liabilities (or actions in respect thereof) arising out of or based on any
untrue statement (or alleged untrue statement) of a material fact contained in
any such registration statement, prospectus, offering circular or other
document, or any omission (or alleged omission) to state therein a material fact
required to be stated therein or necessary to make the statements therein not
misleading, and will reimburse the Company, such directors, officers, persons,
underwriters or control persons for any legal or any other expenses reasonably
incurred in

                                       7
<PAGE>

connection with investigating or defending any such claim, loss, damage,
liability or action, in each case to the extent, but only to the extent, that
such untrue statement (or alleged untrue statement) or omission (or alleged
omission) is made in such registration statement, prospectus, offering circular
or other document in reliance upon and in conformity with written information
furnished to the Company by an instrument duly executed by Holder and stated to
be specifically for use therein; provided, however, that the obligations of
Holder hereunder shall be limited to an amount equal to the net proceeds to
Holder of Registrable Securities sold as contemplated herein.

          (c)  Each party entitled to indemnification under this Section (the
"Indemnified Party") shall give notice to the party required to provide
indemnification (the "Indemnifying Party") promptly after such Indemnified Party
has actual knowledge of any claim as to which indemnity may be sought, and shall
permit the Indemnifying Party to assume the defense of any such claim or any
litigation resulting therefrom, provided that counsel for the Indemnifying
Party, who shall conduct the defense of such claim or litigation, shall be
approved by the Indemnified Party (whose approval shall not unreasonably be
withheld), and the Indemnified Party may participate in such defense at such
party's expense. No Indemnifying Party, in the defense of any such claim or
litigation, shall, except with the consent of each Indemnified Party, consent to
entry of any judgment or enter into any settlement which does not include as an
unconditional term thereof the giving by the claimant or plaintiff to such
Indemnified Party of a release from all liability in respect to such claim or
litigation.

          (d)  If the indemnification provided for in this Section is held by a
court of competent jurisdiction to be unavailable to an Indemnified Party with
respect to any loss, liability, claim, damage or expense referred to herein,
then the Indemnifying Party, in lieu of indemnifying the Indemnified Party,
shall contribute to the amount paid or payable by such Indemnified Party with
respect to such loss, liability, claim, damage or expense in the proportion that
is appropriate to reflect the relative fault of the Indemnifying Party and the
Indemnified Party in connection with the statements or omissions that resulted
in such loss, liability, claim, damage or expense, as well as any other relevant
equitable considerations. The relative fault of the Indemnifying Party and the
Indemnified Party shall be determined by reference to, among other things,
whether the untrue or alleged untrue statement of material fact or the omission
to state a material fact relates to information supplied by the Indemnifying
Party or by the Indemnified Party, and the parties' relative intent, knowledge,
access to information and opportunity to correct or prevent such statement or
omission provided, however, that the obligations of such Indemnifying Party
hereunder shall be limited to an amount equal to the net proceeds to Holder of
Registrable Securities sold as contemplated herein.

          2.8  Information by Holder.  Holder in any registration of its
               ---------------------
Registrable Securities shall furnish to the Company such information regarding
Holder and the distribution proposed by Holder as the Company may request in
writing and as shall be required in connection with any registration,
qualification or compliance referred to in this Section.

          2.9  Delay of Registration.  Holder will not have any right to obtain
               ---------------------
or seek an injunction restraining or otherwise delaying any registration that is
the subject of this Agreement

                                       8
<PAGE>

as the result of any controversy that might arise with respect to the
interpretation or implementation of this Agreement.

          2.10   Acknowledgment of Other Agreements.  Holder acknowledges that
                 ----------------------------------
its has been informed by the Company that other stockholders of the Company
currently hold certain "demand," "piggyback," Form S-3 and other registration
rights that may enable such other stockholders to sell their shares of Common
Stock of the Company prior to the Holder.

          2.11  Assignment.  Notwithstanding anything herein to the contrary,
                -----------
the rights of Holder to cause the Company to register securities granted under
Article 2 may be assigned to a transferee or assignee in connection with the
transfer or assignment of shares of Registrable Securities only if the
transferor or assignor provides prior written notice thereof to the Company and
(i) the transfer of such shares occurs in a distribution from Holder to an
affiliate thereof, or (ii) the transfer of such shares occurs in connection with
a merger or consolidation of Holder or the sale of all or substantially all of
Holder's assets.  Subject to the foregoing restrictions, all rights, covenants
and agreements in Article 2 by or on behalf of the parties hereto will bind and
inure to the benefit of the respective permitted successors and assigns of the
parties hereto.

                                   ARTICLE 3
                                 Miscellaneous

          3.1  Governing Law.  The internal laws of the State of California,
               -------------
irrespective of its choice of law principles, will govern the validity of this
Agreement, the construction of its terms, and the interpretation and enforcement
of the rights and duties of the parties hereto.

          3.2  Severability.  If any provision of this Agreement, or the
               ------------
application thereof, will for any reason and to any extent be invalid or
unenforceable, then the remainder of this Agreement and the application of such
provision to other persons or circumstances will be interpreted so as reasonably
to effect the intent of the parties hereto. The parties further agree to replace
such void or unenforceable provision of this Agreement with a valid and
enforceable provision that will achieve, to the extent possible, the economic,
business and other purposes of the void or unenforceable provision.

          3.3  Counterparts.  This Agreement may be executed in any number of
               ------------
counterparts, each of which will be an original as regards any party whose
signature appears thereon and all of which together will constitute one and the
same instrument.  This Agreement will become binding when one or more
counterparts hereof, individually or taken together, will bear the signatures of
all parties reflected hereon as signatories.

          3.4  Amendment and Waivers.  Any term or provision of this Agreement
               ---------------------
may be amended, and the observance of any term of this Agreement may be waived
(either generally or in a particular instance and either retroactively or
prospectively) only by a writing signed by the party to be bound thereby. The
waiver by a party of any breach hereof or default in the performance hereof will
not be deemed to constitute a waiver of any other default or any succeeding
breach or default.

                                       9
<PAGE>

          3.5  Notices.  All notices and other communications required or
               -------
permitted under this Agreement will be in writing and will be either hand
delivered in person, sent by facsimile, sent by certified or registered first
class mail, postage pre-paid, or sent by nationally recognized express courier
service. Such notices and other communications will be effective upon receipt if
hand delivered or sent by facsimile, five days after mailing if sent by mail,
and one day after dispatch if sent by express courier, to the following
addresses, or such other addresses as any party may notify the other parties in
accordance with this Section:

          If to the Company:

               ONI Systems Corp.
               166 Baypointe Parkway
               San Jose, California 95134
               Attention:  President and General Counsel
               Telecopy:  (408) 965-2665

          with copies to:

               Fenwick & West LLP
               Two Palo Alto Square
               Palo Alto, CA  94306
               Attention:  Richard L. Dickson, Esq.
               Fax Number:  (650) 494-1417

          If to Finisar:

               Finisar Corporation
               1308 Moffett Park Drive
               Sunnyvale, California 94089
               Attention:  President and General Counsel
               Telecopy:  (408) 541-9579

          with a copy to:

               Gray Cary Ware & Freidenrich, LLP
               400 Hamilton Avenue
               Palo Alto, CA  94301
               Attention:  Dennis J. Sullivan, Esq.
               Fax Number:  (650) 327-3699

or to such other address as a party may have furnished to the other parties in
writing pursuant to this Section 3.5.

                                       10
<PAGE>

     3.6  Further Assurances.  Each party agrees to cooperate fully with the
          ------------------
other parties and to execute such further instruments, documents and agreements
and to give such further written assurances as may be reasonably requested by
any other party to evidence and reflect the transactions described herein and
contemplated hereby and to carry into effect the intents and purposes of this
Agreement.

     3.7  Third Party Beneficiary Rights.  No provisions of this Agreement are
          ------------------------------
intended, nor will be interpreted, to provide or create any third party
beneficiary rights or any other rights of any kind in any client, customer,
affiliate, stockholder, partner or any party hereto or any other person or
entity unless specifically provided otherwise herein and, except as so provided,
all provisions hereof will be personal solely between the parties to this
Agreement.

     3.8  Entire Agreement.  This Agreement and the exhibits hereto constitute
          ----------------
the entire understanding and agreement of the parties hereto with respect to the
subject matter hereof and supersede all prior and contemporaneous agreements or
understandings, inducements or conditions, express or implied, written or oral,
between the parties with respect hereto.  The express terms hereof control and
supersede any course of performance or usage of the trade inconsistent with any
of the terms hereof.

        [THE REMAINDER OF THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK.]

                                       11
<PAGE>

     IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of
the date first above written.

ONI SYSTEMS CORP.                           FINISAR CORPORATION


By: /s/  Hugh Martin                        By: /s/  Frank H. Levinson
    -------------------------                   --------------------------------

Name: Hugh Martin                           Name: Frank H. Levinson
      -----------------------                    -------------------------------

Title: CEO                                  Title:  CTO
       ----------------------                     ------------------------------



               [Signature Page to Registration Rights Agreement]

                                       12