Document:

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                                                                     Exhibit 4.2

                               BUY-SELL AGREEMENT

PREAMBLE

        This Buy-Sell Agreement ("Agreement") is made on ________________,
_____, by and among DiCon Fiberoptics, Inc., a California corporation (the
"Company"), and the undersigned persons, (hereinafter, referred to individually
as a "Shareholder," and collectively, the "Shareholders"), with respect to all
of the capital stock now or hereafter held by them, for the purpose of
protecting the Company and the Shareholders, as well as providing continuity for
the Company's business in the event of the occurrence of certain events
discussed in this Agreement. The Shareholders own the outstanding shares of the
Company specified in Exhibit A.

1.      SHARE CERTIFICATES LEGEND REQUIREMENT

        On execution of this Agreement, each Shareholder shall have surrendered
to the Company the certificates representing all of his/her shares so that the
Company can place on such certificates the legend set forth in paragraph 2 of
this Agreement. None of the shares presently owned or subsequently acquired by
the Shareholders shall be sold, pledged, encumbered, transferred or disposed of
in any way, whether voluntarily, involuntarily, or by operation of law, except
under the terms of this Agreement. Except as otherwise provided in this
Agreement, each Shareholder shall have the right to vote his or her shares and
receive the dividends paid on them until the shares are Transferred, (as defined
in paragraph 3.2 below), as provided in this Agreement.

2.      LEGEND ON SHARE CERTIFICATES

        Each share certificate, whether presently owned or subsequently issued,
shall have conspicuously endorsed on its face the following words:

                "Sale, transfer, hypothecation, encumbrance, or disposition of
                the shares represented by this certificate is restricted by the
                provisions of a Buy-Sell Agreement among the Shareholders and
                DiCon Fiberoptics, Inc. of ________________,_______. All
                provisions of the Buy-Sell Agreement are incorporated by
                reference in this certificate. A

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                copy of the Agreement may be inspected at the principal office
                of DiCon Fiberoptics, Inc."

        A copy of this Agreement shall be delivered to the secretary of the
Company and shall be shown to anyone inquiring about it.

3.      RESTRICTIONS ON VOLUNTARY TRANSFERS

        3.1 Applicability. The provisions of this paragraph 3 shall not be
applicable to "Affected Shareholder(s)" as defined in paragraph 6. With respect
to any Affected Shareholder, paragraph 6 shall govern.

        3.2 No Transfer of Shares Without Consent of the Company. Except as
provided in paragraph 4, no Shareholder shall sell, transfer, pledge, encumber,
hypothecate, or in any way dispose of, ("Transfer"), any of his or her shares or
any right or interest in them without obtaining the prior written consent of the
Company and adhering to the provisions of Article 3 of this Agreement.

        3.3 Option of the Company To Purchase. If any Shareholder, (hereinafter
referred to as the "Offering Shareholder"), desires to: (1) have the Company
purchase any or all of his/her/its shares, (2) Transfer any or all of
his/her/its shares to remaining Shareholders, and/or (3) Transfer any or all of
his/her/its shares to any third party, whether to a third party proposed by such
Shareholder or to a third party procured by the Company as specified herein,
such Offering Shareholder shall first have delivered written notice to the
Company, in accordance with paragraph 11.5 of this Agreement, expressing
his/her/its desire to Transfer his/her/its shares. The notice shall specify the
number of shares proposed to be Transferred, and the name and address of the
Offering Shareholder's proposed transferee, if any. Promptly on receipt of the
notice, the Company shall forward a copy of the notice and the executed
counterpart to each member of the Company's board of directors, ("Board of
Directors"), and within thirty (30) days thereafter a meeting of the Board of
Directors shall be called, noticed, and held to consider the proposed Transfer.
For ninety (90) days following receipt of notice by the Company from the
Offering Shareholder, it shall have the option, but not the obligation, to
purchase, to the extent permitted by California law then in effect, any or all
of the shares at the price determined in the same manner as proved in paragraph
7 of this Agreement.

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        If the Company exercises its option to purchase any or all of the shares
within such ninety (90) day period, the Company shall give written notice of
that fact to the Offering Shareholder. The Company shall pay the purchase price
in the manner specified in paragraph 8 of this Agreement.

        3.4 Option of the Company to Offer Shares to Third Party(ies) or to
Remaining Shareholders.

                (a) Purchase By Third Party(ies) or Remaining Shareholders. If
the Company does not purchase within the ninety (90) day period any or all of
the shares specified in the Offering Shareholder's notice described in paragraph
3.3 above, the Board of Directors shall have the option, but not the obligation,
to (1) offer to any third party(ies) acceptable to the Board of Directors the
right to purchase any of the shares not purchased by the Company at the price
determined in the same manner as provided in paragraph 7 of this Agreement;
and/or (2) offer to the remaining Shareholders the right to purchase pro rata,
in accordance with paragraph 3.4(c)(ii) below, any of the shares not purchased
by the Company at the price determined in the same manner as provided in
paragraph 7 of this Agreement. If the Board of Directors elects to offer to
third party(ies) and/or to the remaining Shareholders, (hereinafter, such third
party(ies) and remaining Shareholders referred to generally, without distinction
as "Offeree(s)"), the right to purchase any or all of the shares not purchased
by the Company, the Board of Directors shall, prior to the expiration of the
ninety (90) day period specified in paragraph 3.3 above, deliver written notice
in accordance with paragraph 11.5 to such Offeree(s) specifying the number of
shares offered.

                (b) Sole Discretion of Board of Directors. With respect to the
implementation of this paragraph 3.4, the Board of Directors has the complete
discretion to offer or not to offer, any or all of the shares to a third
party(ies) acceptable to the Board of Directors, and/or to the remaining
Shareholders. Furthermore, the Board of Directors shall not be under any
obligation to first offer any or all of the shares to the remaining Shareholders
before it offers any or all of the shares to third party(ies). The Board of
Directors, within its sole and unfettered discretion, may elect to make no offer
at all, or to offer any or all of the shares first to such third party(ies), or
to the remaining Shareholders, or it may simultaneously offer some of the shares
to such third party(ies), and some of the shares to the remaining Shareholders.
Provided however, that if the

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Board of Directors elects to offer any or all of the shares to the remaining
Shareholders, any such offer shall be pro-rata in accordance with paragraph
3.4(c)(ii) below.

                (c) Period of Time to Purchase by Third Party(ies) and/or
Remaining Shareholders. If the Board of Directors elects to offer to any
Offeree(s) the right to purchase any or all of the shares not purchased by the
Company, and timely delivers written notice to such Offerees as specified in
paragraph 3.4(a) above, for sixty (60) days following such delivery, such
Offeree(s) shall have the option, but not the obligation to purchase, to the
extent permitted by California law, any or all of the shares at the price
determined in the same manner as provided in paragraph 7 of this Agreement.

                        (i) Third Party(ies) Right to Purchase. If such third
party(ies) specified in paragraph 3.4(c) above desires to exercise such option
to purchase any or all of the shares offered to him/her/it by the Board of
Directors, such third party(ies) shall deliver, within the sixty (60) day period
described in paragraph 3.4(c) above, a written election to purchase all of
shares offered to him/her/it, or a specified number of them. Such third
party(ies) shall pay the purchase price calculated in accordance with paragraph
7, deliver payment in the manner specified in paragraph 8 of this Agreement, and
shall sign an amended copy of this Agreement as a condition precedent to
receiving the shares.

                        (ii) Remaining Shareholders' Right to Purchase. Any
Shareholder desiring to acquire any or all of the shares offered to him/her/it
by the Board of Directors shall deliver to the Company and the Offering
Shareholder within the sixty (60) day period described in paragraph 3.4(c)
above, written election to purchase all of the offered shares or a specified
number of them. Provided however, that in order to be eligible to purchase any
or all of the shares offered by the Board of Directors as provided in this
Agreement, a shareholder of the Company shall have first executed this Agreement
or an amended version thereof. If the total number of shares in the elections
exceeds the number of available shares, each Shareholder shall have priority, up
to the number of shares specified in his or her notice of election to purchase,
to purchase the available shares, in proportion that the number of the Company's
shares, that he or she holds, bears to the total number of the Company's shares
held by all Shareholders electing to purchase. The shares not purchased on such
priority basis shall be allocated in one or more successive allocations to those
Shareholders electing to purchase more than the number of shares to which they
have a priority right, up to the number of shares specified in their

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respective notices, in the proportion that the number of shares held by each of
them bears to the number of shares held by all of them.

        3.5 Release to Transfer to Proposed Transferee, If Any. If the Offering
Shareholder's notice to the Company as specified in paragraph 3.3 has designated
a proposed transferee, any shares not purchased by the Company, and/or third
party(ies), and/or the remaining Shareholders as prescribed under this Article
3, may be Transferred to the proposed transferee at any time within sixty (60)
days after expiration of the sixty (60) day period specified in paragraph
3.4(c), but only at the price specified in paragraph 7 and on the terms
specified in paragraph 8. The transferee shall hold such shares subject to the
provisions of this Agreement. No Transfer shall be made after the end of the
sixty (60) day period, nor shall any change in the terms of Transfer be
permitted without a new notice of intention to Transfer and compliance with the
requirement of this paragraph. Conversely, if the Offering Shareholder's notice
to the Company as specified in paragraph 3.3 fails to designate a proposed
transferee, any shares not purchased by the Company, and/or third party(ies),
and/or the remaining Shareholders as prescribed under this Article 3, shall
continue to be held by the Offering Shareholder and subject to all of the terms
and conditions of this Agreement, including without limitation, restrictions
prohibiting Transfer of the shares. Any Transfer by any shareholder in violation
of this Agreement shall be null and void and of no effect.

4.      EXCEPTION FOR TRANSFERS TO FAMILY TRUSTS

        Notwithstanding anything in paragraph 3 above, the Company and the
remaining Shareholders shall have no option to purchase, and this Agreement
shall not otherwise restrict, the transfer by any Shareholder of any or all of
his/her shares to his/her Family Trust, as defined below. A "Family Trust"
means, a living trust, (or such other trust established by the Shareholder for
his/her estate planning purposes), into which such Shareholder has transferred
some or all of his/her shares. Such Family Trust shall meet the following
requirements: (1) the trustee must be the Shareholder establishing such Family
Trust, ("Shareholder Trustee"), except that such Family Trust may have one or
more co-trustees in addition to such Shareholder Trustee; (2) the right to vote
all the shares held in the Family Trust must, by its terms, be vested solely in
the Shareholder Trustee; and (3) in the event that such Shareholder Trustee
suffers any of the "Triggering Events" specified in paragraph 6, he/she shall be
considered an "Affected

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Shareholder," and the shares held in the Family Trust shall be subject to the
provisions of paragraph 6.

5.      OBLIGATIONS OF TRANSFEREES

        Each transferee or any subsequent transferee of shares in the Company,
or any interest in such shares, shall hold the shares or interest in the shares
subject to all provision of this Agreement and shall make no further Transfers
except as provided in this Agreement. Transfer of the shares shall not be
entered on the books of the Company until an amended copy of this Agreement has
been executed by the prospective transferee. Failure or refusal to sign such an
amended copy of this Agreement shall not relieve any transferee from any
obligations under this Agreement.

6.      OPTION TO PURCHASE UPON INVOLUNTARY TRANSFER, ENCUMBRANCE, DEATH, MENTAL
        INCAPACITY OR ATTEMPTED TRANSFERS IN VIOLATION OF THIS AGREEMENT

        6.1 Company Option to Purchase Affected Stock; Option of the Board of
Directors to Offer Affected Stock to Third Party(ies) and/or Remaining
Shareholders. Upon the occurrence of any of the following events, ("Triggering
Event(s)"), with respect to a Shareholder (the "Affected Shareholder"), the
Company, and/or a third party designated by the Board of Directors, and/or the
remaining Shareholders shall have the option to purchase all or any part of the
Affected Shareholder's shares in the Company, (herein called the "Affected
Stock"), in accordance with the procedures set forth in paragraphs 6.2 through
6.6.

        (a) Filing of a petition in bankruptcy by the Affected Shareholder or by
any person against the Affected Shareholder which petition is not dismissed or
vacated within 60 days of its filing;

        (b) Assignment of the Affected Shareholder's assets for the benefit of
creditors or an appointment of a receiver to take possession of the shares of
the Company owned by the Affected Shareholder which assignment or appointment is
not revoked or vacated within 60 days;

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        (c) Pledging, hypothecating or otherwise encumbering the shares of the
Company as security for any debt;

        (d) Any marital property settlement purporting to give the spouse of the
Affected Shareholder any legal or beneficial interest in the shares which is not
dismissed or rescinded within 60 days;

        (e) The entry of any final order, decree or judgment of court in a
marital dissolution or any other proceeding purporting to give the spouse of the
Affected Shareholder any legal or beneficial interest in the shares which is not
dismissed or vacated within 60 days;

        (f) Filing of a complaint by the Affected Shareholder for involuntary
dissolution of the Company under applicable provisions of the California
Corporations Code;

        (g) Any attempted Transfer of the shares not specifically permitted by
other provisions of this Agreement;

        (h) Death of the Affected Shareholder; or

        (i) Mental incapacity of the Affected Shareholder such that he or she is
substantially unable to manage his or her own financial resources or resist
fraud or undue influence.

        6.2 Company Option to Purchase Affected Stock . Within ninety (90) days
following the date of actual notice to the Company of an event specified in
Paragraph 6.1, a meeting of the Board of Directors shall be held for the purpose
of considering the occurrence of such event. During this ninety (90) day period,
the Company shall have the option, but not the obligation, to purchase, to the
extent permitted by California law then in effect, any or all of the shares at
the price determined in the same manner as provided in paragraph 7 of this
Agreement. If the Company exercises its option to purchase any or all of the
shares within such ninety (90) day period, the Company shall give written notice
of that fact to the Affected Shareholder. The Company shall pay the purchase
price in the manner specified in paragraph 8 of this Agreement.

        6.3 Option of the Company to Offer Affected Stock to Third Party(ies) or
to Remaining Shareholders.

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                (a) Purchase of Affected Stock By Third Party(ies) or Remaining
Shareholders. If the Company does not elect under paragraph 6.2 to purchase all
of the Affected Stock, the Board of Directors shall have the option, but not the
obligation, to (1) offer to a third party(ies) acceptable to the Board of
Directors the right to purchase any of the shares of Affected Stock not
purchased by the Company at the price determined in the same manner as provided
in paragraph 7 of this Agreement; and/or (2) offer to the remaining Shareholders
the right to purchase pro rata, in accordance with paragraph 6.3(c)(ii) below,
any of the shares not purchased by the Company at the price determined in the
same manner as provided in paragraph 7 of this Agreement. If the Board of
Directors elects to offer to such Offeree(s) the right to purchase any or all of
the shares of Affected Stock not purchased by the Company, the Board of
Directors shall, prior to the expiration of the ninety (90) day period specified
in paragraph 6.2 above, deliver written notice in accordance with paragraph 11.5
to such Offeree(s) specifying the number of shares of Affected Stock offered.
Such notice shall describe the Triggering Event under Paragraph 6.1 giving rise
to the option to purchase, state the action, if any, taken by the Company with
respect to the Affected Stock, and state the number of Affected Stock available
for purchase such by the Offeree(s) at a price determined in the same manner as
provided in paragraph 7 of this Agreement.

                (b) Sole Discretion of Board of Directors to Offer Affected
Stock. With respect to the implementation of this paragraph 6.3, the Board of
Directors has the complete discretion to offer or not to offer, any or all of
the shares of Affected Stock to third party(ies) acceptable to the Board of
Directors, and/or to the remaining Shareholders. Furthermore, the Board of
Directors shall not be under any obligation to first offer any or all of the
shares of Affected Stock to the remaining Shareholders before it offers any or
all of the shares to third party(ies). The Board of Directors, within its sole
and unfettered discretion, may elect to make no offer at all, or to offer any or
all of the shares of Affected Stock first to such third party(ies), or to the
remaining Shareholders, or it may simultaneously offer some of the shares to
such third party(ies), and some of the shares to the remaining Shareholders.
Provided however, that if the Board of Directors elects to offer any or all of
the shares of the Affected Stock to the remaining Shareholders, any such offer
shall be pro-rata in accordance with paragraph 6.3(c)(ii) below.

                (c) Period of Time to Purchase Affected Stock by Third
Party(ies) and/or Remaining Shareholders. If the Board of Directors elects to
offer to any Offeree(s) the right to

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purchase any or all of the shares of Affected Stock not purchased by the
Company, and timely delivers written notice to such Offerees as specified in
paragraph 6.3(a) above, for sixty (60) days following such delivery, such
Offeree(s) shall have the option, but not the obligation to purchase, to the
extent permitted by California law, any or all of the shares of Affected Stock
at the price determined in the same manner as provided in paragraph 7 of this
Agreement.

                        (i) Third Party(ies) Right to Purchase Affected Stock.
If such third party(ies) specified in paragraph 6.3(c) above desires to exercise
such option to purchase any or all of the shares of Affected Stock offered to
him/her/it by the Board of Directors, such third party(ies) shall deliver,
within the sixty (60) day period described in paragraph 6.3(c) above, a written
election to purchase all of shares offered to him/her/it, or a specified number
of them. Such third party(ies) shall pay the purchase price calculated in
accordance with paragraph 7, deliver payment in the manner specified in
paragraph 8 of this Agreement, and shall sign an amended copy of this Agreement
as a condition precedent to receiving the shares.

                        (ii) Remaining Shareholders' Right to Purchase Affected
Stock. Any Shareholder desiring to acquire any or all of the shares of Affected
Stock offered to him/her/it by the Board of Directors shall deliver to the
Company and the Affected Shareholder within the sixty (60) day period described
in paragraph 6.3(c) above, written election to purchase all of such offered
shares of Affected Stock or a specified number of them. Provided however, that
in order to be eligible to purchase any or all of the shares of Affected Stock
offered by the Board of Directors as provided in this Agreement, a shareholder
of the Company shall have first executed this Agreement or an amended version
thereof. Within sixty (60) days after the date of delivery of the notice to the
remaining Shareholders, or within sixty (60) days after the last date on which
the notice should have been given if the Company has for any reason failed to
give the notice, any Shareholder desiring to acquire any part or all of the
Affected Stock shall deliver to the Company a written election to purchase the
Affected Stock or specified number of them. The rights and obligations of the
remaining Shareholders under this option and notice procedure shall be identical
to those described in paragraph 3.4(c)(ii).

        6.4 Disposition of Affected Stock Not Purchased. The period during
which the Company, and/or any third party(ies) designated by the Board of
Directors, and/or remaining Shareholders may exercise their options to purchase
the Affected Stock commences on the date of actual notice to the Company of an
event specified in Paragraph 6.1 and ends upon the earlier

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of (1) the date as of which the Board of Directors has determined in its sole
discretion not to purchase any or all of the Affected Stock, nor offer any or
all of the Affected Stock for purchase by a third party(ies) and/or the
remaining Shareholders and has delivered notice of the same to the Affected
Shareholder as specified in paragraph 11.5, (2) the expiration of the successive
ninety (90) and sixty (60) day periods during which the Company, and/or such
third party(ies) and the remaining Shareholders may make their elections, or (3)
the date as of which the Company, and/or any third party(ies), and/or remaining
Shareholders have made their final elections. If the Board of Directors has
delivered notice to the Affected Shareholder that the Company shall not be
purchasing any or all of the Affected Stock nor offering any or all of the
Affected Stock for purchase by third party(ies) and/or the remaining
Shareholders, or if at the end of the option period, the Company, and/or such
third party(ies), and/or the remaining Shareholders have not elected to purchase
all of the Affected Stock, the shares of Affected Stock not elected to be
purchased shall be automatically released from restrictions solely for the
purpose of subjecting such Affected Stock to any applicable proceedings or
agreements connected with the Triggering Events, and any Transferee of the
Affected Stock under such proceedings or agreements shall acquire such Affected
Stock subject to the terms, conditions and restrictions of this Agreement,
including, without limitation, restrictions against further Transfer of such
shares, as if each such Transferee signed this Agreement. Any Transfer of the
Affected Stock shall be subject to any legends referred to under paragraph 2
which are or should have been imprinted on the certificates representing the
shares Transferred, and the Company shall have the right to require the Affected
Shareholder or his or her representative to furnish to the Company an opinion of
counsel in form and substance and from counsel satisfactory to the Company to
the effect that such legends have been complied with.

        6.5 Loss of Shareholder Status. In the event the Company, and/or any
third party(ies) designated by the Board of Directors, and/or the remaining
Shareholders have elected to purchase all of the Affected Stock, the Affected
Shareholder shall lose his or her status as a shareholder from the date of
delivery of written notice indicating the election of the Company, and/or such
third party(ies) and/or the remaining Shareholders to purchase all of the
Affected Stock, notwithstanding the fact that title to the Affected Stock has
not yet been Transferred. From and after such date, the Affected Shareholder
shall have no rights to receive dividends or other distributions, to participate
in corporate affairs, such as attending and voting at meetings of shareholders,
and receive information concerning the Company.

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        6.6 Purchase Price. The purchase price and payment terms of any
Affected Stock purchased by the Company, and/or any third party designated by
the board of directors, and/or remaining Shareholders shall be determined under
paragraphs 7 and 8 of this Agreement.

7.      VALUATION

        The Board of Directors shall valuate the shares of the Company as set
forth below.

        7.1 Regular Valuations. The Board of Directors shall valuate the shares
of the Company two times per year at approximately six (6) month intervals; the
first valuation shall be conducted promptly after the completion of accounting
for the Company's last fiscal year, and the second valuation, shall be conducted
after the completion of accounting for Company operations for the six (6) month
period immediately following the first valuation, (the first valuation and the
second valuation hereinafter referred to generally and without distinction as
"Regular Valuation(s)"). For each Regular Valuation, the Board of Directors
shall issue two valuations: (1) the value of the shares as of the completion of
Company operations for that six (6) month interval, and (2) a forecast which
estimates the value of the shares six (6) months immediately thereafter, (such
forecast hereinafter referred to as "Valuation Forecast").

        7.2 Calculation of Current Value of the Shares. For purposes of
establishing the purchase price of the shares pursuant to Articles 3 and 6 of
this Agreement at any given time, the Board of the Directors shall calculate the
current value of the shares, as of the applicable valuation dates specified in
paragraphs 7.2(a) and 7.2(b) below, by interpolating or taking a linear weighted
average between the value of the shares as of the completion of Company
operations for the six (6) month interval of the last Regular Valuation, and the
value of the shares as estimated in the corresponding Valuation Forecast,
(hereinafter, the result of such linear interpolation referred to as "the
Current Value").

                (a) Valuation Date for Proposed Voluntary Transfers. The
valuation date in determining the Current Value of the shares applicable to any
proposed voluntary Transfer pursuant to Article 3 of this Agreement, shall be on
the sixtieth (60th) day after the Offering Shareholder has delivered written
notice to the Company expressing his/her/its desire to Transfer any or all of
his/her/its shares as specified in paragraph 3.3.

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                (b) Valuation Date for Affected Stock. The valuation date in
determining the Current Value of the shares applicable to any Affected Stock
pursuant to Article 7 of this Agreement, shall be on the sixtieth (60th) day
after the occurrence of any Triggering Event as defined in paragraph 6. 1.

        7.3 Valuation Methodology; Valuations in Addition to Regular Valuations.
Regular Valuations shall be done in accordance with a method approved from time
to time by the Board of Directors within its sole discretion, and detailed in a
document entitled "Evaluating DiCon Common, Methodology," and made available to
the Shareholders. However, the undersigned acknowledges that valuation of the
Company's shares is not an exact science and therefore, notwithstanding anything
herein to the contrary, the undersigned agrees that the Board of Directors may
in its sole discretion, amend Evaluating DiCon Common, Methodology, as it deems
appropriate, including without limitation, changing or deleting valuation
methods, formulas, rates or variables, or attaching more or less emphasis to
some methods or factors over others to reflect changing economic conditions and
circumstances. In addition to the Regular Valuations, the Board of Directors may
valuate the shares at such other times as it determines within its sole
discretion, or may devise and apply such other means to calculate or interpolate
the value of the shares at any particular time between Regular Valuations.

8.      TERMS OF PAYMENT

        The purchase price for the Offered Stock or Affected Stock, as the case
may be, shall be paid severally and not jointly by each buyer in proportion to
the shares acquired by such buyer as follows: each buyer shall pay in full
its/his/her respective portion of the purchase price within sixty (60) days
after the end of its/his/her applicable option period provided in paragraphs
3.3, (as pertaining to the purchase of Offered Stock by the Company); 3.4, (as
pertaining to the purchase of Offered Stock offered by the Board of Directors to
third party(ies) and/or to the remaining Shareholders); 6.2, (as pertaining to
the purchase of Affected Stock by the Company); or 6.3, (as pertaining to the
purchase of Affected Stock offered by the Board of Directors to third party(ies)
and/or to the remaining Shareholders).

9.      APPOINTMENT OF SECRETARY OF COMPANY TO HOLD SHARE CERTIFICATES AND AS
        ATTORNEY-IN-FACT.

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        For convenience in implementing the terms of this Agreement, each of the
Shareholders hereby appoints the Secretary of the Company (i) as custodian to
hold his/her share certificates; and (ii) as his/her attorney-in-fact in his/her
behalf for purposes of effectuating the provisions of this Agreement. Promptly
after signing this Agreement, each Shareholder shall deposit with the Secretary
all certificates representing his/her shares in the Company, endorsed in blank.

10.     TERMINATION

        10.1 Events Causing Termination. This Agreement shall terminate only in
accordance with paragraph 11.6 or in the event the Company is dissolved.

        10.2 Cancellation of Stock Legend. Upon termination of this Agreement,
the Secretary shall promptly endorse upon each of the certificates representing
issued and outstanding shares of stock in the Company a statement indicating the
date of termination of this Agreement.

11.     MISCELLANEOUS

        11.1 Additional Documents. Each Shareholder agrees to take such action
and execute such documents, including without limitation a will with appropriate
instructions to the executor, as are necessary or desirable to carry out the
terms, conditions and restrictions of this Agreement. The failure of a
Shareholder to so instruct his or her executor or comply with other instructions
shall not, however, affect the validity or enforceability of this Agreement.
Each Shareholder agrees to timely deliver duly executed certificates
representing all shares to be purchased under this Agreement.

        11.2 Binding on Successors. Subject to the specific provisions of this
Agreement, this Agreement shall be binding upon and inure to the benefit of the
parties hereto and their heirs, successors, assigns and personal
representatives.

        11.3 Savings Clause. If any one or more of the provisions of this
Agreement shall for any reason be held or declared to be invalid, illegal or
unenforceable in any respect, such invalidity, illegality or unenforceability
shall not affect any other provisions of this Agreement.

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        11.4 Attorneys' Fees. In the event any party hereto brings an action
(including without limitation any complaint, cross-complaint, counterclaim,
third-party claim, appeal or bankruptcy proceeding) to enforce or to interpret
the terms of this Agreement, or to collect damages as the result of an alleged
breach hereof, the party prevailing shall be entitled to recover from the
nonprevailing party or parties reasonable attorneys' fees and costs incurred in
such action by the prevailing party.

        11.5 Notices. Each notice permitted or required to be given under this
Agreement shall be in writing and executed by the person giving such notice. Any
such notice shall be sufficiently given or delivered if accomplished by personal
delivery or by depositing the notice in the United States Mail, registered or
certified, postage prepaid, or with an air courier service, in either case
addressed, in the case of the Company, to the principal office of the Company,
and, in the case of a Shareholder, to his or her latest address on record with
the Company. A mailed notice shall be deemed delivered upon deposit with the
United States Postal Service.

        11.6 Amendment and Enforcement. This Agreement or specific rights or
obligations hereunder may be amended, waived, delayed, terminated or otherwise
changed by, and only by, the written consent of the Company, which is approved
by the Company's Board of Directors, and the vote or written consent of
Shareholders holding more than fifty percent (50%) of the outstanding shares of
the Company.

        11.7 Governing Laws and Definitions. This Agreement shall be governed
by and construed in accordance with the laws of the State of the California
applicable to contracts made among residents of, and to be performed entirely
within, the State of California. Unless otherwise defined in this Agreement,
definitions in the California General Corporation Law shall apply to terms used
in this Agreement. References to "shares" means shares issued by the Company.
When this Agreement refers to any vote or consent of holders of outstanding
shares, the Shareholder's shares shall be included in that vote or consent
unless expressly excluded by specific language in this Agreement, whether or not
any alleged conflict of interest exists. Whenever the singular is used in this
Agreement, it includes the plural. Whenever the masculine gender is used, it
includes the feminine or neuter gender.

        11.8 Integration. This Agreement represents the entire integrated
agreement between the undersigned parties and supersede all prior written and
oral negotiations, representations and

                                       14
<PAGE>

agreements concerning the subject matter hereof. Nothing in this Agreement shall
imply or be considered to constitute any terms of employment of any Shareholder
by the Company, and this Agreement shall in no way limit, impair or affect the
right of the Company or the Shareholder to terminate the employment of any
Shareholder with or without cause (subject, however, to any written employment
agreement applicable to the Shareholder and signed by the Company and
Shareholder).

COMPANY:                                SHAREHOLDER:
DiCon Fiberoptics, Inc., a California
corporation

By
   -----------------------------        ----------------------------------------
        Ho-Shang Lee                    (Signature)
Title:  President

By
   -----------------------------        ----------------------------------------
        Anthony T. Miller               (Print Name)

Title:  Secretary

                                       15
<PAGE>

                                    EXHIBIT A
                       SHAREHOLDERS AND OUTSTANDING SHARES

                                       16
<PAGE>

                                 SPOUSES CONSENT

        I am the spouse of _______________ who has signed the foregoing Buy-Sell
Agreement (the "Agreement"). I have read the Agreement and consent to all
provisions of the Agreement. I further agree to take no action to delay or
hinder any transfer of shares in the Company in accordance with the Agreement. I
agree that any community property rights and any other interest I may have in
these shares shall be subject and subordinate to the requirements of the
Agreement and that the Company and other shareholders need not seek any further
consent from me and may deal solely with my spouse in connection with all
matters under the Agreement.

                                        Effective_________________,_____________

                                        ________________________________________
                                        (Signature)

                                        ________________________________________
                                        (Print Name)

                                       17<PAGE>

                                                                   Exhibit 4.2.1

                                                         Employee No.___________

                               Buy-Sell Agreement

        This Agreement is entered into as of _____________, between DiCon
Fiberoptics, Inc. ("Company") and the undersigned person ("Shareholder"), with
respect to all of the shares in the Company now or hereafter owned by
Shareholder ("Shares").

1. Restrictions on Transfers

        1.1 No Transfer without Adhering to Agreement. None of the Shares or any
right or interest in the Shares shall be sold, pledged, hypothecated,
encumbered, transferred or disposed of in any way, whether voluntarily or
involuntarily or by operation of law, except under the terms of this Agreement.

        1.2 Legend on Share Certificates. Each certificate for Shares shall have
conspicuously endorsed on it the following words:

        "Sale, pledge, hypothecation, encumbrance, transfer or disposition of
        the shares represented by this certificate is restricted by the
        provisions of a Buy-Sell Agreement between Shareholder and DiCon
        Fiberoptics, Inc. All provisions of the Buy-Sell Agreement are
        incorporated by reference in this certificate. A copy of the Buy-Sell
        Agreement may be inspected at the principal office of DiCon Fiberoptics,
        Inc."

2. Restrictions on Voluntary Transfers

                2.1 No Transfer without Adhering to Article 2. Shareholder shall
not sell, pledge, hypothecate, encumber, transfer or dispose of in any way
("Transfer") any of the Shares or any right or interest in the Shares, except in
compliance with the requirements of this Article 2.

                2.2 Option to Purchase. If Shareholder desires to Transfer any
or all of the Shares to any third party, Shareholder shall first have delivered
written notice to the Company expressing Shareholder's desire to Transfer the
Shares. The notice shall specify the number of Shares proposed to be
Transferred, and the name and address of Shareholder's proposed transferee.
During the 60 day period following receipt of notice by the Company from
Shareholder, the Company or its designee shall have the option to purchase any
or all of the Shares proposed to be transferred at the price determined as
provided in Article 5. If the

                                       1
<PAGE>

Company or its designee exercises its option, the Company or its designee shall
give written notice of that fact to Shareholder.

                2.3 Transfer to Proposed Transferee. Any Shares not purchased by
the Company or its designee as prescribed under this Article 2 may be
Transferred to the proposed transferee at any time within 60 days after
expiration of the 60 day period specified in Paragraph 2.2, but only at the
price specified in Article 5. No Transfer shall be made after the end of the 60
day period specified in this Paragraph 2.3, nor shall any change in the terms of
Transfer be permitted without a new notice of intention to Transfer and
compliance with the requirements of this Article 2. Any Transfer by Shareholder
in violation of this Agreement shall be null and void and of no effect.

3. Obligations of Transferees

        Each transferee and each subsequent transferee of any Shares or any
right or interest in any Shares shall hold the Shares or right or interest in
the Shares subject to all the provisions of this Agreement and shall make no
further Transfers except as provided in this Agreement. Transfer of the Shares
shall not be entered on the books of the Company until a copy of this Agreement
has been executed by the prospective transferee. Failure or refusal to sign a
copy of this Agreement shall not relieve any transferee from any obligations
under this Agreement.

4. Company Option to Purchase on Triggering Events

        4.1 Option to Purchase. Upon the occurrence of any of the following
events ("Triggering Events") with respect to Shareholder or any Shares or any
right or interest in any Shares, the Company or its designee shall have the
option to purchase any or all of the Shares in accordance with the procedures
set forth in Paragraph 4.2:

                (a) Filing of a petition in bankruptcy by Shareholder or by any
person against Shareholder.

                (b) Assignment of Shareholder's assets for the benefit of
creditors or an appointment of a receiver to take possession of any Shares.

                (c) Pledging, hypothecating or otherwise encumbering any Shares
as security for any debt.

                (d) Any marital property settlement purporting to give the
spouse of Shareholder any legal or beneficial interest in any Shares.

                (e) The entry of any final order, decree or judgment of court in
a marital dissolution or any other proceeding purporting to give the spouse of
Shareholder any legal or beneficial

                                       2
<PAGE>

interest in any Shares.

                (f) The death of Shareholder.

                (g) Any attempted Transfer of any Shares not specifically
permitted by other provisions of this Agreement.

                (h) The termination for any reason of Shareholder's employment
with the Company.

        4.2 Purchase Procedures. During the 60 day period following the date of
actual notice to the Company of a Triggering Event, the Company or its designee
shall have the option to purchase any or all of the Shares at the price
determined as provided in Article 5. If the Company or its designee exercises
its option, the Company or its designee shall give written notice of that fact
to Shareholder.

5. Valuation

        5.1 Regular Valuations. The Board of Directors of the Company values the
shares of the Company two times per year at approximately six month intervals;
the first valuation is conducted after the completion of accounting for the
Company's last fiscal year, and the second valuation is conducted after the
completion of accounting for Company operations for the six month period
following the last fiscal year (the first valuation and the second valuation
hereinafter referred to generally as "Regular Valuations").

        5.2 Calculation of Current Value of the Shares. The purchase price of
Shares pursuant to Articles 2 and 4 shall be the current value of the shares of
the Company as of the applicable valuation dates specified in subparagraphs (a)
and (b) below ("the Current Value").

                (a) Valuation Date for Proposed Voluntary Transfers. The
valuation date in determining the Current Value of Shares pursuant to Article 2
shall be the day Shareholder has delivered written notice to the Company
expressing Shareholder's desire to Transfer Shares as specified in Paragraph
2.2.

                (b) Valuation Date for Affected Stock. The valuation date in
determining the Current Value of Shares pursuant to Article 4 shall be the day
of the occurrence of any Triggering Event.

        5.3 Valuation Methodology; Valuations in Addition to Regular Valuations.
Regular Valuations shall be done in accordance with a method approved from time
to time by the Board of Directors of the Company within its sole discretion, and
detailed in a document entitled "Evaluating DiCon Common, Methodology", and made
available to Shareholder. However, Shareholder acknowledges that valuation of
the Company's shares is not an exact

                                       3
<PAGE>

science and therefore, notwithstanding anything herein to the contrary,
Shareholder agrees that the Board of Directors may in its sole discretion amend
Evaluating DiCon Common, Methodology as it deems appropriate, including without
limitation, changing or deleting valuation methods, formulas, rates or
variables, or attaching more or less emphasis to some methods or factors over
others to reflect changing economic conditions and circumstances. In addition to
the Regular Valuations, the Board of Directors may value the shares at such
other times as it determines within its sole discretion, or may devise and apply
such other means to calculate or interpolate the value of the shares at any
particular time between Regular Valuations.

6. Appointment of Company Secretary to Hold Certificates and as Attorney-in-Fact

        For convenience in implementing the terms of this Agreement, Shareholder
hereby appoints the Secretary of the Company (i) as custodian to hold the Share
certificates; and (ii) as Shareholder's attorney-in-fact on Shareholder's behalf
for purposes of effectuating the provisions of this Agreement. Immediately upon
receipt, Shareholder shall deposit with the Secretary all certificates
representing the Shares, endorsed in blank.

7. Term of Agreement

        The restrictions on Transfer of the Shares set forth in this Agreement
shall terminate upon any of the following:

        7.1 Determination of Board. The determination of the Board of Directors
of the Company that this Agreement shall be terminated.

        7.2 Public Offering. The consummation of a public offering for any of
the common stock of the Company registered under the Securities Act of 1933, as
amended, on SEC Form S-1 or any successor form.

8. General Provisions

        8.1 Notices. Any communications between the parties hereto to be given
in writing shall be given by mailing the same, postage prepaid, or by telex,
cable, facsimile or personal delivery addressed, in the case of the Company, to
the principal office of the Company, and in the case of Shareholder, to
Shareholder's latest address on record with the Company.

        8.2 Successors. This Agreement shall inure to the benefit of the
successors, assigns and designees of the Company, and is binding upon the heirs,
successors, assigns, administrators, executors and other legal representatives
of Shareholder.

                                       4
<PAGE>

        8.3 Governing Law. This Agreement shall be governed by and construed
under the laws of the State of the California without regard to California
conflict of law principles.

DiCon Fiberoptics, Inc.
                                        ----------------------------------------
                                        (Signature of Shareholder)

By
   ---------------------------------    ----------------------------------------
   Ho-Shang Lee                         (Print name of Shareholder)
Title: President

By
   ---------------------------------
   Anthony T. Miller
Title: Secretary

                                       5
<PAGE>

                                 Spouses Consent

        I am the spouse of _____________________ who has signed the foregoing
Buy-Sell Agreement. I have read the Buy-Sell Agreement and consent to all
provisions of the Buy-Sell Agreement. I agree to take no action to delay or
hinder any transfer of the Shares in accordance with the Buy-Sell Agreement. I
agree that any community property rights and any other right or interest I may
have in the Shares shall be subject and subordinate to the requirements of the
Buy-Sell Agreement and that the Company need not seek any further consent from
me and may deal solely with my spouse in connection with all matters under the
Buy-Sell Agreement.

Dated:
      ------------------------------

------------------------------------
(Signature of spouse)

------------------------------------
(Print name of spouse)

                                       6

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