<PAGE>   1
                                                                   EXHIBIT 10.13



                     EARLY EXERCISE STOCK PURCHASE AGREEMENT
                            FOR APRIL 26, 1999 OPTION
                       (INCLUDING RIGHT OF FIRST REFUSAL)

        THIS AGREEMENT is made by and between Vixel Corporation, a Delaware
corporation (the "Corporation"), and James M. McCluney ("Purchaser").

        NOW, THEREFORE, IT IS AGREED between the parties as follows:

        1.      Purchaser hereby agrees to purchase from the Corporation, and
the Corporation hereby agrees to sell to Purchaser, an aggregate of one million
five hundred thousand (1,500,000) shares of the common stock (the "Stock") of
the Corporation, for an exercise price of $2.05 per share. The closing hereunder
shall occur at the offices of the Corporation on the date of this Agreement or
at such other time and place as the parties may mutually agree upon in writing.
At the closing, Purchaser shall deliver three (3) stock assignments in the form
of Exhibit B, duly endorsed (with date and number of shares left blank), joint
escrow instructions (the "Joint Escrow Instructions") in the form of Exhibit C,
duly executed by Purchaser, and the total exercise price (including endorsed
certificates representing the appropriate number of shares of the Corporation's
common stock if a portion of the total exercise price is to be paid by common
stock). At the closing or as soon thereafter as practicable, the Corporation
shall deliver to the Escrow Agent (as defined in paragraph 10 below) share
certificates for all of the Stock that is to be subject to the Purchase Option
(as defined in paragraph 2 below), and shall deliver share certificates to
Purchaser for all of the Stock, if any, that is not to be subject to the
Purchase Option. Upon the request of Purchaser during the term of the escrow,
certificates for shares that are no longer subject to the Purchase Option shall
be delivered to Purchaser.

        2.      The Stock to be purchased by Purchaser pursuant to this
Agreement shall be subject to the following option ("Purchase Option"):

                (a)     In the event that Purchaser shall cease to be an
employee of the Corporation for any reason (including his death), or no reason,
with or without cause, the Purchase Option may be exercised. The Corporation
shall have the right at any time within ninety (90) days after such cessation of
employment to purchase from Purchaser or his personal representative, as the
case may be, at the price per share paid by Purchaser pursuant to this Agreement
("Option Price"), up to but not exceeding the number of shares of the Stock set
forth on Exhibit A hereto which is incorporated herein by this reference. For
purposes of this Section 2, Purchaser will be considered to be "employed" by the
Company if Purchaser is providing bona fide consulting services to the Company.
Accordingly, notwithstanding the foregoing, the Purchase Option may not be
exercised and the shares of Stock subject to this Agreement will continue to
vest during any period that Purchaser is a bona fide consultant of the Company.
Unless otherwise determined by the Company's Board of Directors, for purposes of
this Section 2, the term "bona fide consulting services" shall only include
services provided to the Company by Optionee for such compensation as the
Company's Board of Directors may approve and shall not include services directly
or indirectly related to Purchaser's services as a member of the Company's Board
of Directors.


                                       1.
<PAGE>   2
                (b)     In addition, and without limiting the foregoing Purchase
Option, if at any time during the term of the Purchase Option, there occurs an
Acquisition (as defined in the Nonstatutory Option Agreement dated April 26,
1999) (the "Option Agreement"), or if following an Acquisition Purchaser's
employment is terminated by the Company other than for Cause, or is terminated
by Purchaser for Good Reason (as such terms are defined in such agreement), then
the Purchase Option shall be terminated as to the number of shares subject to
accelerated vesting pursuant to Section 2 of such agreement.

                (c)     The Corporation shall be entitled to pay for any shares
purchased pursuant to its Purchase Option, at the Corporation's option, in cash,
by offset against any indebtedness owing to the Corporation by Purchaser,
including, without limitation, any note given in payment for the Stock, or a
combination of both.

        3.      The Purchase Option may be exercised by giving written notice of
exercise delivered or mailed as provided in paragraph 15 below. Upon providing
of such notice and payment or tender of the purchase price, the Corporation
shall become the legal and beneficial owner of the Stock being purchased and all
rights and interests therein or related thereto.

        4.      If from time to time during the term of the Purchase Option
there is any stock dividend or liquidating dividend or distribution of cash
and/or property, stock split or other change in the character or amount of any
of the outstanding securities of the Corporation, then, in such event, any and
all new, substituted or additional securities or other property to which
Purchaser is entitled by reason of his ownership of Stock will be immediately
subject to the Purchase Option and be included in the word "Stock" for all
purposes of the Purchase Option with the same force and effect as the shares of
Stock then subject to the Purchase Option. While the total Option Price shall
remain the same after each such event, the Option Price per share of Stock upon
exercise of the Purchase Option shall be appropriately adjusted.

        5.      [INTENTIONALLY DELETED.]

        6.      CORPORATION'S RIGHT OF FIRST REFUSAL.

                (a)     Subject to the limitations of subparagraph 6(b), in the
event that, prior to the date of the first registration of an equity security of
the Corporation under Section 12 of the Securities Exchange Act of 1934,
Purchaser desires to sell, encumber or otherwise transfer all or any portion of
the Stock received upon the exercise of Purchaser's Option, or any interest
therein, Purchaser will be required to first give written notice of the intent
to transfer to the Secretary of the Corporation. The notice will name the
proposed transferee and state the number of shares of Stock to be transferred,
the proposed consideration, and all other terms and conditions of the proposed
transfer. The Corporation and/or its assignee(s) will have the right (the "Right
of First Refusal") at any time within thirty (30) days after receipt of such
notice to purchase any portion of the Stock specified in the notice at the price
and upon the terms set forth in such notice (the "Notice Price"). In the case of
a gift, property settlement or other transfer in which the proposed transferee
is not paying the full price for the shares, the price will be deemed to be the
fair market value of the Stock at such time as determined in good faith by the
Board of


                                       2.
<PAGE>   3
Directors. In the event the Corporation and/or its assignee(s) elects to
purchase all or any portion of the Stock, it will provide Purchaser with written
notice of its election and cash payment at the Notice Price within thirty (30)
days after receipt of the transfer notice. If, however, the terms of payment set
forth in the transfer notice were other than cash against delivery, the
Corporation and/or its assignee(s) will pay for the Stock on the same terms and
conditions as set forth in the transfer notice. In the event the Corporation
and/or its assignee(s) do not elect to acquire all of the shares specified in
the transfer notice, Purchaser may, within the sixty (60)-day period following
the expiration of the Corporation's Right of First Refusal, transfer any portion
of the Stock specified in the notice which was not acquired by the Corporation
and/or its assignee(s) on the terms specified in the original notice. All shares
so sold by Purchaser will continue to be subject to the same restrictions as
before the transfer.

                (b)     The following transactions shall be exempt from the
provisions of subparagraph 6(a): (i) Purchaser's transfer of any or all shares
held either during such Purchaser's lifetime or on death by will or intestacy to
such Purchaser's immediate family or to any custodian or trustee for the account
of such Purchaser or such Purchaser's immediate family and (ii) Purchaser's bona
fide pledge or mortgage of any shares with a commercial lending institution,
provided that any subsequent transfer of said shares to said institution shall
be conducted in the manner set forth in this Agreement. "Immediate family" as
used herein shall mean spouse, lineal descendant, father, mother, brother, or
sister of the Purchaser making such transfer;

        In any case, the transferee, assignee, or other recipient shall receive
and hold such Stock subject to the provisions of this Agreement, and there shall
be no further transfer of such Stock except in accord with this Agreement.

        7.      All certificates representing any shares of Stock of the
Corporation subject to the provisions of this Agreement shall have endorsed
thereon legends in substantially the following form:

                        (i)     "The shares represented by this certificate are
subject to an option and a right of first refusal set forth in an agreement
between the corporation and the registered holder, or his predecessor in
interest, a copy of which is on file at the principal office of this
corporation. Any transfer or attempted transfer of any shares subject to such
option is void without the prior express written consent of the issuer of these
shares."

                        (ii)    "These securities have not been registered under
the Securities Act of 1933. They may not be sold, offered for sale, pledged or
hypothecated in the absence of an effective registration statement as to the
securities under said Act or an opinion of counsel satisfactory to the
corporation that such registration is not required."

        8.      Purchaser acknowledges that he is aware that the Stock to be
issued to him by the Corporation pursuant to this Agreement has not been
registered under the Securities Act of 1933, as amended (the "Act"), on the
basis that no distribution or public offering of the Stock is to be effected,
and in this connection acknowledges that the Corporation is relying on the
following representations. In this connection, Purchaser warrants and represents
to the Corporation that he is acquiring the Stock for investment and not with a
view to or for sale in connection with any distribution of the Stock or with any
present intention of distributing or selling the Stock and he does not presently
have reason to anticipate any change in circumstances or any particular


                                       3.
<PAGE>   4
occasion or event which would cause him to sell the Stock. Purchaser recognizes
that the Stock must be held indefinitely unless it is subsequently registered
under the Act or an exemption from such registration is available and, further,
recognizes that the Corporation is under no obligation to register the Stock or
to comply with any exemption from such registration.

        9.      Purchaser is aware that the Stock may not be sold pursuant to
Rule 144 adopted under the Act unless certain conditions are met and until
Purchaser has held the Stock for at least one (1) year. Among the conditions for
use of Rule 144 is the availability of specified current public information
about the Corporation. Purchaser recognizes that the Corporation presently has
no plans to make such information available to the public. Whether or not the
Purchase Option is exercised or has lapsed, Purchaser further agrees not to make
any disposition of any of the Stock in any event unless and until: (A) There is
then in effect a registration statement under the Act covering such proposed
disposition and such disposition is made in accordance with such registration
statement; or (B) (I) Purchaser shall have notified the Corporation of the
proposed disposition and shall have furnished the Corporation with a detailed
statement of the circumstances surrounding the proposed disposition, and (II)
Purchaser shall have given the Corporation an opinion of counsel, which opinion
and counsel shall be satisfactory to the Corporation, to the effect that such
disposition will not require registration of the Stock under the Act.

        10.     As security for his faithful performance of the terms of this
Agreement and to insure the availability for delivery of Purchaser's Stock upon
exercise of the Purchase Option herein provided for, Purchaser agrees, at the
closing hereunder (or as soon thereafter as practicable), to deliver (or have
the Corporation deliver on the Purchaser's behalf) to and deposit with the
Secretary of the Corporation ("Escrow Agent"), as Escrow Agent in this
transaction, three (3) stock assignments duly endorsed (with date and number of
shares left blank) in the form attached hereto as Exhibit B, together with a
certificate or certificates evidencing all of the Stock subject to the Purchase
Option; said documents are to be held by the Escrow Agent and delivered by said
Escrow Agent pursuant to the Joint Escrow Instructions of the Corporation and
Purchaser set forth in Exhibit C attached hereto and incorporated herein by this
reference, which instructions shall also be delivered to the Escrow Agent at the
closing hereunder (or as soon thereafter as practicable).

        11.     Except for transfers permitted pursuant to Section 9 of the
Option Agreement, purchaser shall not sell or transfer any of the Stock subject
to the Purchase Option or any interest therein so long as such Stock is subject
to the Purchase Option.

        12.     The Corporation shall not be required (i) to transfer on its
books any shares of Stock of the Corporation which shall have been sold or
transferred in violation of any of the provisions set forth in this Agreement or
(ii) 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 shall have been
so transferred.

        13.     Subject to the provisions of paragraphs 11 and 12 above,
Purchaser (but not any unapproved transferee) shall, during the term of this
Agreement, exercise all rights and privileges of a stockholder of the
Corporation with respect to the Stock.


                                       4.
<PAGE>   5
        14.     The parties agree to execute such further instruments and to
take such further action as reasonably may be necessary to carry out the intent
of this Agreement.

        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 any United States Post Office Box, by registered or certified mail
with postage and fees prepaid, addressed to the other party hereto at his
address hereinafter shown below his signature or at such other address as such
party may designate by ten (10) days' advance written notice to the other party
hereto.

        16.     This Agreement shall bind and inure to the benefit of the
successors and assigns of the Corporation and, subject to the restrictions on
transfer herein set forth, inure to the benefit of and be binding upon
Purchaser, his heirs, executors, administrators, successors, and assigns.
Without limiting the generality of the foregoing, the Purchase Option of the
Corporation hereunder shall be assignable by the Corporation at any time or from
time to time, in whole or in part.

        IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the 30th day of April, 1999.

                                  VIXEL CORPORATION

                                  By:  /s/ Kurtis L. Adams
                                       -------------------------------
                                       Title: CFO
                                              -------------------------------

                                       11911 Northcreek Parkway South
                                       Suite 100
                                       Bothell, WA 98011




                                   PURCHASER


                                   /s/ James M. McCluney
                                   ------------------------------------------
                                   James M. McCluney


                                       5.
<PAGE>   6
                                    EXHIBIT A
                                       TO
                          NONSTATUTORY OPTION AGREEMENT
                                     VESTING

<TABLE>
<CAPTION>
        Date of Vesting                                  Number of Shares
<S>                                                      <C>

             4/26/00                                          375,000

             5/26/00                                           31,250

             6/26/00                                           31,250

             7/26/00                                           31,250

             8/26/00                                           31,250

             9/26/00                                           31,250

            10/26/00                                           31,250

            11/26/00                                           31,250

            12/26/00                                           31,250

             1/26/01                                           31,250

             2/26/01                                           31,250

             3/26/01                                           31,250

             4/26/01                                           31,250

             5/26/01                                           31,250

             6/26/01                                           31,250

             7/26/01                                           31,250

             8/26/01                                           31,250

             9/26/01                                           31,250

            10/26/01                                           31,250

            11/26/01                                           31,250

            12/26/01                                           31,250
</TABLE>


                                       6.
<PAGE>   7
<TABLE>
<S>                                                      <C>
             1/26/02                                           31,250

             2/26/02                                           31,250

             3/26/02                                           31,250

             4/26/02                                           31,250

             5/26/02                                           31,250

             6/26/02                                           31,250

             7/26/02                                           31,250

             8/26/02                                           31,250

             9/26/02                                           31,250

            10/26/02                                           31,250

            11/26/02                                           31,250

            12/26/02                                           31,250

             1/26/03                                           31,250

             2/26/03                                           31,250

             3/26/03                                           31,250

             4/26/03                                           31,250
                                                            =========
                                                            1,500,000
                                                            =========
</TABLE>


                                       7.
<PAGE>   8
                                    EXHIBIT B

                      ASSIGNMENT SEPARATE FROM CERTIFICATE


        FOR VALUE RECEIVED and pursuant to that certain Early Exercise Stock
Purchase Agreement (the "Agreement") dated as of April 30, 199, James M.
McCluney hereby sells, assigns and transfers unto Vixel Corporation, a Delaware
corporation (the "Corporation") One million five hundred thousand (1,500,000)
shares of Common Stock of the Corporation standing in the undersigned's name on
the books of the Corporation represented by Certificate No. _____ herewith, and
does hereby irrevocably constitute and appoint the Secretary of the Corporation
attorney to transfer the said stock on the books of the Corporation with full
power of substitution in the premises. This Assignment may be used only in
accordance with and subject to the terms and conditions of the Agreement, in
connection with the repurchase of shares of Common Stock issued to the
undersigned pursuant to the Agreement, and only to the extent that such shares
remain subject to the Company's Purchase Option under the Agreement.


Dated:  April 30, 1998                 /s/ James M. McCluney
                                       -----------------------------------------
                                       [Signature]



                                       James M. McCluney


                                       8.
<PAGE>   9
                                    EXHIBIT C

                            JOINT ESCROW INSTRUCTIONS


Vixel Corporation
Attention:  Secretary

Dear Sir:

        As Escrow Agent for both Vixel Corporation, a Delaware corporation (the
"Company"), and the undersigned purchaser of stock of the Company ("Purchaser"),
you are hereby authorized and directed to hold the documents delivered to you
pursuant to the terms of that certain Early Exercise Stock Purchase Agreement
(the "Agreement"), dated April 26, 1999, to which a copy of these Joint Escrow
Instructions is attached as Exhibit B, in accordance with the following
instructions:

        1.      In the event the Company or an assignee shall elect to exercise
the Purchase Option set forth in the Agreement, the Company or its assignee will
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 any 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 against the
simultaneous delivery to you of the purchase price (which may include suitable
acknowledgment of cancellation of indebtedness) of the number of shares of stock
being purchased pursuant to the exercise of the Purchase 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 specified in the Agreement.
Purchaser hereby irrevocably constitutes and appoints you as his
attorney-in-fact and agent for the term of this escrow to execute with respect
to such securities and other property all documents of assignment and/or
transfer and all stock certificates necessary or appropriate to make all
securities negotiable and complete any transaction herein contemplated.

        4.      This escrow shall terminate upon expiration or closing of the
exercise of the Purchase Option, whichever occurs first.

        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 same to Purchaser and shall be discharged of
all further obligations hereunder; provided, however, that


                                       9.
<PAGE>   10
if at the time of termination of this escrow you are advised by the Company that
the property subject to this escrow is the subject of a pledge or other security
agreement, you shall deliver all such property to the pledgeholder or other
person designated by the Company.

        6.      Except as otherwise provided in these Joint Escrow Instructions,
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 or their assignees. 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 of any
court, 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, authority 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
any 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 (including,
without limitation, the firm of Cooley Godward LLP) 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 Secretary of the Company or if you shall resign by
written notice to each party. In the event of any such termination, the Company
may appoint any officer or assistant officer of the Company as successor Escrow
Agent and Purchaser hereby confirms the appointment of such successor or
successors as his attorney-in-fact and agent to the full extent of your
appointment.


                                      10.
<PAGE>   11
        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.

        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, you may (but are not obligated to) retain in your possession without
liability to anyone all or any part of said securities until such dispute 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 any United States Post Office Box, by registered or certified mail
with postage and fees prepaid, addressed to each of the other parties hereunto
entitled at the following addresses specified below, or at such other addresses
as a party may designate by ten days' written notice to each of the other
parties hereto:

        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 agreement will be governed by, and construed in accordance
with, the internal laws (excluding the law of conflicts) of the State of
Delaware.


                                      11.
<PAGE>   12
        18.     This instrument shall be binding upon and inure to the benefit
of the parties hereto and their respective successors and permitted assigns. It
is understood and agreed that references to "you" or "your" herein refer to the
original Escrow Agent and to any and all successor Escrow Agents. It is
understood and agreed that the Company may at any time or from time to time
assign its rights under the Agreement and these Joint Escrow Instructions in
whole or in part.

                                       Very truly yours,

                                       VIXEL CORPORATION


                                       By: /s/ KURTIS L. ADAMS
                                          ------------------------------------
                                          Name: Kurtis L. Adams
                                          Title: CFO

                                       PURCHASER:



                                       /s/ JAMES M. MCCLUNEY
                                       ---------------------------------------
                                       James M. McCluney


ESCROW AGENT:


Secretary


Address:


2595 Canyon Blvd., Ste. 250
Boulder, CO 80302


                                      12.