<PAGE>
                                                                    Exhibit 4.18

THE SECURITIES REPRESENTED BY THIS WARRANT AND THE COMMON STOCK ISSUABLE THEREBY
HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE
"SECURITIES ACT"), OR ANY OTHER APPLICABLE SECURITIES LAW AND ACCORDINGLY, THE
SECURITIES REPRESENTED BY THIS WARRANT MAY NOT BE RESOLD, PLEDGED OR
TRANSFERRED, EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER, OR IN
A TRANSACTION EXEMPT FROM REGISTRATION UNDER, THE SECURITIES ACT AND IN
ACCORDANCE WITH ANY OTHER APPLICABLE SECURITIES LAWS.

     
                               WARRANT

                     to Purchase Common Stock of

                         PHOTRAN CORPORATION

                    Expiring on February 9, 2003


This Warrant to Purchase Common Stock (the "Warrant") certifies that for value
received, St. James Capital Partners, L.P., a Delaware limited partnership, or
its transferees or assignees (the "Holder"), is entitled to purchase from the
Company (as hereinafter defined), in whole or in part, 1,225,000 shares of duly
authorized, validly issued, fully paid and nonassessable shares of Common Stock
(as hereinafter defined) at an Exercise Price (as hereinafter defined) per share
of $4.00, subject, however, to the provisions and upon the terms and conditions
hereinafter set forth. The number of Warrants (as hereinafter defined), the
number of shares of Common Stock purchasable hereunder, and the Exercise Price
therefor are subject to adjustment as hereinafter set forth.  This Warrant and
all rights hereunder shall expire at 5:00 p.m., Houston, Texas time, on February
9, 2003 (the "Expiration Date").

                             ARTICLE I

                            DEFINITIONS

As used herein, the following terms shall have the meanings set forth below:

   1.1  "COMPANY" shall mean Photran Corporation, a Minnesota 
corporation, and shall also include any successor thereto with respect 
to the obligations hereunder, by merger, consolidation, share exchange 
or otherwise.

   1.2  "COMMON STOCK" shall mean and include the Company's Common 
Stock, no par value, issued and authorized on the date of the issue of 
this Warrant and shall also include (i) in case of any reorganization, 
reclassification, consolidation, merger, share exchange or sale, 
transfer or other disposition of assets of the character referred to 
in Section 4.5 herein, the stock or other securities provided for in 
Section 4.5 herein, and (ii) any other shares of Common Stock of the 
Company into which such shares of Common Stock may be converted.

   1.3  "EXERCISE PRICE" shall mean the purchase price of $4.00 per 
share of Common Stock payable upon exercise of the Warrants, as 
adjusted from time to time pursuant to the provisions hereof.

   1.4  "MARKET PRICE" for any day, when used with reference to Common 
Stock, shall mean the 

                                       62

<PAGE>

price of said Common Stock averaged over a period of ten (10) 
consecutive Trading Days prior to the date as of which the 
determination is to be made determined as follows: (i) the last 
reported sale price for the Common Stock on each Trading Day on the 
principal securities exchange on which the Common Stock is listed or 
admitted to trading or if no such sale takes place on such date, the 
average of the closing bid and asked prices thereof as officially 
reported, or, if not so listed or admitted to trading on any 
securities exchange, the last sale price for the Common Stock on the 
National Association of Securities Dealers National Market System or 
Small Cap Market on such date, or, if there shall have been no trading 
on such date or if the Common Stock shall not be listed on such 
system, the average of the closing bid and asked prices in the 
over-the-counter market as furnished by any NASD member firm selected 
from time to time by the Company for such purpose in each such case, 
unless otherwise provided herein; or (ii) if the Common Stock shall 
not be listed or admitted to trading as provided in clause (i) above, 
the fair market value of the Common Stock as determined in good faith 
by the Board of Directors of the Company.

   1.5  "NOTE" shall mean the 10% Convertible Promissory Note of the 
Company in the amount of $3,500,000 payable to St. James Capital 
Partners, L.P. dated as of the date hereof.

   1.6  "OUTSTANDING," when used with reference to Common Stock, shall 
mean (except as otherwise expressly provided herein) at any date as of 
which the number of shares thereof is to be determined, all issued 
shares of Common Stock, except shares then owned or held by or for the 
account of the Company.

   1.7  "PERSON" means any individual, corporation, limited liability 
company, partnership, joint venture, association, joint stock company, 
trust, estate, unincorporated organization or other entity or 
government or any agency or political subdivision thereof.

   1.8  "TRADING DAYS" shall mean any days during the course of which 
the principal securities exchange on which the Common Stock is listed 
or admitted to trading is open for the exchange of securities.

   1.9  "WARRANT" shall mean the right upon exercise to purchase one 
Warrant Share.

   1.10 "WARRANT SHARES" shall mean the shares of Common Stock 
purchased or purchasable by the Holder hereof upon the exercise of the 
Warrants.

                             ARTICLE II

                       EXERCISE OF WARRANTS

   2.1  METHOD OF EXERCISE.  The Warrants represented hereby may be 
exercised by the Holder hereof, at any time and from time to time on 
or after the date hereof until 5:00 p.m., Houston, Texas time, on the 
Expiration Date. To exercise the Warrants, the Holder hereof shall 
deliver to the Company, at the Warrant Office designated herein, (i) a 
written notice in the form of the Subscription Notice attached as an 
exhibit hereto, stating therein the election of such Holder to 
exercise the Warrants in the manner provided in the Subscription 
Notice; (ii) payment in full of the Exercise Price (A) in cash or by 
bank check for all Warrant Shares purchased hereunder, or (B) through 
a "cashless" or "net-issue" exercise of each such Warrant ("Cashless 
Exercise"); the Holder shall exchange each Warrant subject to a 
Cashless Exercise for that number of Warrant Shares determined by 
multiplying the number of Warrant Shares issuable hereunder by a 
fraction, the numerator of which shall be the difference between (x) 
the Market Price and (y) the Exercise Price for each such Warrant, and 
the denominator of which shall be the Market Price; the Subscription 
Notice shall set forth the calculation upon which the Cashless 
Exercise is based; and (iii) this Warrant. The Warrants shall be 
deemed to be exercised on the date of receipt by the Company of the 
Subscription Notice, accompanied by payment for the Warrant Shares and 
surrender of this Warrant, as aforesaid, and such date is referred to 
herein as the "Exercise Date". Upon such exercise, the Company shall, 

                                       63

<PAGE>

as promptly as practicable and in any event within five business days, 
issue and deliver to such Holder a certificate or certificates for the 
full number of the Warrant Shares purchased by such Holder hereunder, 
and shall, unless the Warrants have expired, deliver to the Holder 
hereof a new Warrant representing the number of Warrants, if any, that 
shall not have been exercised, in all other respects identical to this 
Warrant.  As permitted by applicable law, the Person in whose name the 
certificates for Common Stock are to be issued shall be deemed to have 
become a Holder of record of such Common Stock on the Exercise Date 
and shall be entitled to all of the benefits of such Holder on the 
Exercise Date, including, without limitation, the right to receive 
dividends and other distributions for which the record date falls on 
or after the Exercise Date and to exercise voting rights with respect 
thereto.

   2.2  EXPENSES AND TAXES.  The Company shall pay all expenses and 
taxes (including, without limitation, all documentary, stamp, transfer 
or other transactional taxes) other than income taxes attributable to 
the preparation, issuance or delivery of the Warrants and of the 
shares of Common Stock issuable upon exercise of the Warrants.

   2.3  RESERVATION OF SHARES.  The Company shall reserve at all times 
so long as the Warrants remain outstanding, free from preemptive 
rights, out of its authorized but unissued shares of Common Stock, 
solely for the purpose of effecting the exercise of the Warrants, a 
sufficient number of shares of Common Stock to provide for the 
exercise of the Warrants.

   2.4  VALID ISSUANCE.  All shares of Common Stock that may be issued 
upon exercise of the Warrants will, upon issuance by the Company, be 
duly and validly issued, fully paid and nonassessable and free from 
all taxes, liens and charges with respect to the issuance thereof and, 
without limiting the generality of the foregoing, the Company shall 
take no action or fail to take any action which will cause a contrary 
result (including, without limitation, any action that would cause the 
Exercise Price to be less than the par value, if any, of the Common 
Stock.

   2.5  PURCHASE AGREEMENT.  The Warrants represented hereby are part 
of a duly authorized issuance and sale of warrants to purchase Common 
Stock issued and sold pursuant to that certain Agreement for Purchase 
and Sale dated as of the date hereof (the "Agreement"), between the 
Company and the Holder.  The Holder shall be entitled to the rights to 
registration under the Securities Act of 1933, as amended (the 
"Securities Act") and any applicable state securities or blue sky laws 
to the extent set forth in the Registration Rights Agreement between 
the Company and the Holder dated as of the date hereof (the 
"Registration Rights Agreement"). The terms of the Agreement and the 
Registration Rights Agreement are hereby incorporated herein for all 
purposes and shall be considered a part of this Warrant as if they had 
been fully set forth herein. Notwithstanding the previous sentence, in 
the event of any conflict between the provisions of the Agreement or 
the Registration Rights Agreement and this Warrant, the provisions of 
this Warrant shall control. 

   2.6  ACKNOWLEDGMENT OF RIGHTS.  At the time of the exercise in 
accordance with the terms hereof and upon the written request of the 
Holder hereof, the Company will acknowledge in writing its continuing 
obligation to afford to such Holder any rights (including, without 
limitation, any right to registration of the Warrant Shares) to which 
such Holder shall continue to be entitled after such exercise in 
accordance with the provisions of this Warrant; provided, however, 
that if the Holder hereof shall fail to make any such request, such 
failure shall not affect the continuing obligation of the Company to 
afford to such Holder any such rights.

   2.7  NO FRACTIONAL SHARES.  The Company shall not be required to 
issue fractional shares of Common Stock on the exercise of this 
Warrant. If more than one Warrant shall be presented for exercise at 
the same time by the same Holder, the number of full shares of Common 
Stock which shall be issuable upon 

                                       64

<PAGE>

such exercise shall be computed on the basis of the aggregate number 
of whole shares of Common Stock purchasable on exercise of the 
Warrants so presented. If any fraction of a share of Common Stock 
would, except for the provisions of this Section, be issuable on the 
exercise of this Warrant, the Company shall pay an amount in cash 
calculated by it to be equal to the Market Price of one share of 
Common Stock at the time of such exercise multiplied by such fraction 
computed to the nearest whole cent. 

                                ARTICLE III

                                 TRANSFER

   3.1  WARRANT OFFICE.  The Company shall maintain an office for 
certain purposes specified herein (the "Warrant Office"), which office 
shall initially be the Company's offices at 21875 Grenada Avenue, 
Lakeville, Minnesota 55044, and may subsequently be such other office 
of the Company or of any transfer agent of the Common Stock in the 
continental United States as to which written notice has previously 
been given to the Holder. The Company shall maintain, at the Warrant 
Office, a register for the Warrants in which the Company shall record 
the name and address of the Person in whose name this Warrant has been 
issued, as well as the name and address of each permitted assignee of 
the rights of the registered owner hereof.

   3.2  OWNERSHIP OF WARRANTS.  The Company may deem and treat the 
Person in whose name the Warrants are registered as the Holder and 
owner hereof (notwithstanding any notations of ownership or writing 
hereon made by anyone other than the Company) for all purposes and 
shall not be affected by any notice to the contrary until presentation 
of this Warrant for registration of transfer as provided in this 
Article III. Notwithstanding the foregoing, the Warrants represented 
hereby, if properly assigned in compliance with this Article III, may 
be exercised by an assignee for the purchase of Warrant Shares without 
having a new Warrant issued.

   3.3  RESTRICTIONS ON TRANSFER OF WARRANTS.  Subject to compliance 
with the requirements of Section 3.4 hereof, these Warrants may be 
transferred, in whole or in part, by the Holder. Subject to the 
restrictions set forth in this Section, the Company, from time to 
time, shall register the transfer of the Warrants in such books upon 
surrender of this Warrant at the Warrant Office properly endorsed or 
accompanied by appropriate instruments of transfer and written 
instructions for transfer. Upon any such transfer and upon payment by 
the Holder or its transferee of any applicable transfer taxes, new 
Warrants shall be issued to the transferee and the transferor (as 
their respective interests may appear) and the surrendered Warrants 
shall be cancelled by the Company. The Company shall pay all taxes 
(other than securities transfer taxes or income taxes) and all other 
expenses and charges payable in connection with the transfer of the 
Warrants pursuant to this Section.

        3.3.1     RESTRICTIONS IN GENERAL.  The Holder of the Warrants 
     agrees that it will not transfer the Warrants prior to delivery to the 
     Company of written notice of such transfer until registration of such 
     Warrant Shares under the Securities Act and any applicable state 
     securities or blue sky laws has become effective.

   3.4  COMPLIANCE WITH SECURITIES LAWS.  Subject to the terms of the 
Registration Rights Agreement and Section 3.4.1 hereof, the Holder 
understands and agrees that the following restrictions and limitations 
shall be applicable to all Warrants and Warrant Shares and to all 
resales or other transfers thereof pursuant to the Securities Act:

        3.4.1     The Holder of the Warrants agrees that it will not 
     transfer the Warrant or the Warrant Shares (collectively, the "Seller 
     Securities") unless registration of the Seller Securities under the 
     Securities Act and any applicable state securities or blue sky laws 
     has become effective or the Seller Securities are exempt therefrom. 
     Notwithstanding the preceding sentence or Section 3.3, 

                                       65

<PAGE>

     however, St. James Capital Partners, L.P., as the initial holder of the 
     Warrants, may transfer the Seller Securities to its partners of record as 
     of September 30, 1997 at any time and St. James Capital Partners, L.P. 
     represents that any partner receiving any of the Seller Securities is, 
     or will be at the time of such transfer, an "Accredited Investor" as 
     that term is defined in Rule 501(a) of Regulation D as promulgated by 
     the Securities Exchange Commission under the Securities Act. The 
     partners of St. James Capital Partners, L.P. shall not be entitled to 
     transfer the Seller Securities prior to completion of registration of 
     the Company's Common Stock. St. James Capital Partners, L.P. may at 
     any time grant a security interest in the Seller Securities to its 
     lender or lenders. Any lender or lenders to which St. James Capital 
     Partners, L.P. grants a security interest in the Seller Securities 
     shall be entitled to exercise all remedies to which it is entitled by 
     contract or by law, including (without limitation) transferring the 
     Seller Securities into its own name or into the name of any purchaser 
     at any sale undertaken in connection with enforcement by such lender 
     of its remedies. Prior to any transfer (other than the grant of a 
     security interest) as provided herein, the transferor shall provide 
     written notice to the Company and an opinion of counsel to the effect 
     that the proposed transfer is exempt from registration under all 
     applicable securities laws, all in form and substance reasonably 
     satisfactory to the Company. The Company shall pay all reasonable 
     attorneys' fees and costs incurred by the transferor as a result of 
     rendering such opinion or opinions of counsel. The Company, however, 
     may treat Holder as the owner hereof for all purposes until the 
     Warrant or the certificates evidencing the Warrant Shares shall have 
     been surrendered for transfer as hereinafter provided. Upon surrender 
     of the Warrant or the certificates evidencing the Warrant Shares duly 
     executed by Holder or its agent or attorney, the Company shall execute 
     and deliver a new Warrant or a certificate or certificates for the 
     Warrant Shares in the name of the assignee or assignees and in the 
     denominations specified in such instrument of assignment, and the old 
     Warrant or certificate or certificates evidencing the Warrant Shares 
     shall promptly be canceled.  

        3.4.2     A legend in substantially the following form will be 
     placed on the certificate(s) evidencing the Warrant Shares:

        "THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN 
        REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE 
        "SECURITIES ACT"), OR ANY OTHER APPLICABLE SECURITIES LAW AND, 
        ACCORDINGLY, THE SECURITIES REPRESENTED BY THIS CERTIFICATE MAY NOT BE
        RESOLD, PLEDGED, OR OTHERWISE TRANSFERRED, EXCEPT PURSUANT TO AN 
        EFFECTIVE REGISTRATION STATEMENT UNDER, OR IN A TRANSACTION EXEMPT 
        FROM REGISTRATION UNDER, THE SECURITIES ACT AND IN ACCORDANCE WITH ANY 
        OTHER APPLICABLE SECURITIES LAWS."
     
        3.4.3     Stop transfer instructions will be imposed with 
     respect to the Seller Securities so as to restrict resale or other 
     transfer thereof, subject to this Section 3.4.

                              ARTICLE IV

                            ANTI-DILUTION

   4.1  ANTI-DILUTION PROVISIONS.  The Exercise Price shall be subject 
to adjustment from time to time as provided herein. Upon each 
adjustment of the Exercise Price, the Holder of this Warrant shall 
thereafter be entitled to purchase, at the Exercise Price resulting 
from such adjustment, the number of Warrant Shares of Common Stock 
obtained by multiplying the Exercise Price in effect immediately prior 
to such adjustment by the number of shares purchasable pursuant hereto 
immediately prior to such adjustment and dividing the product thereof 
by the Exercise Price resulting from such adjustment.

                                       66

<PAGE>


   4.2  ADJUSTMENT OF EXERCISE PRICE UPON ISSUANCE OF COMMON STOCK.

        4.2.1     If and whenever after the date hereof the Company 
     shall issue or sell any Common Stock for no consideration or for a 
     consideration per share less than the Exercise Price, the Exercise 
     Price shall be reduced (but not increased, except as otherwise 
     specifically provided herein) to the lower price per share (calculated 
     to the nearest one-ten thousandth of a cent, but in any event not less 
     than $.001 per share).

        4.2.2     Notwithstanding the provisions of this Section 4.2, 
     no adjustment shall be made in the Exercise Price in the event that 
     the Company issues, in one or more transactions, (i) Common Stock or 
     convertible securities upon exercise of any options issued to 
     officers, directors or employees of the Company pursuant to a stock 
     option plan or an employment, severance or consulting agreement as now 
     or hereafter in effect, in each case approved by the Board of 
     Directors (provided that the aggregate number of shares of Common 
     Stock which may be issuable, including options issued prior to the 
     date hereof, under all such employee plans and agreements shall at no 
     time exceed 725,000; (ii) Common Stock upon exercise of the Warrants 
     or any other warrant issued pursuant to the terms of the Agreement or 
     otherwise issued to Holder; (iii) Common Stock upon exercise of any 
     stock purchase warrant or option (other than the options referred to 
     in clause (i) above) or other convertible security outstanding on the 
     date hereof (other than any shares of Common Stock issuable on 
     conversion of any promissory note held by any shareholder of the 
     Company; provided, however, that no adjustment shall be made in the 
     Exercise Price in the event the Company issues Common Stock on 
     conversion of the convertible promissory note made by the Company in 
     favor of Steven King, the Chairman of the Board of the Company, in the 
     principal amount of $200,000, in connection with the Bridge Loan 
     Agreement dated as of August 8, 1993, as amended and restated March 
     15, 1996 and April 9, 1997, and as amended February 9, 1998, and as it 
     exists as of the date hereof); or (iv) Common Stock issued to Shenzen 
     WABO Group Company Limited pursuant to the Settlement Agreement 
     between the Company and Shenzen WABO Group Company Limited.  In 
     addition, for purposes of calculating any adjustment of the Exercise 
     Price as provided in this Section, all of the shares of Common Stock 
     issuable pursuant to any of the foregoing shall be assumed to be 
     outstanding prior to the event causing such adjustment to be made.
     
        4.2.3     In case at any time after the date hereof the Company 
     shall in any manner grant (whether directly or by assumption in a 
     merger or otherwise) any rights to subscribe for or to purchase Common 
     Stock (including the right to convert any note held by any shareholder 
     of the Company (in whole or in part) into shares of Common Stock) or 
     any options, except for options issued to of officers, directors or 
     employees of the Company pursuant to a stock option plan now or 
     hereafter in effect, for the purchase of Common Stock or any stock or 
     securities convertible into or exchangeable for Common Stock (such 
     convertible or exchangeable stock or securities being herein called 
     "Convertible Securities"), whether or not such rights or options or 
     the right to convert or exchange any such Convertible Securities are 
     immediately exercisable, and the price per share for which shares of 
     Common Stock are issuable upon the exercise of such rights or options 
     or upon conversion or exchange of such Convertible Securities 
     (determined by dividing (i) the total amount, if any, received or 
     receivable by the Company as consideration for the granting of such 
     rights or options, plus the minimum aggregate amount of additional 
     consideration, if any, payable to the Company upon the exercise of 
     such rights or options, or plus, in the case of such rights or options 
     that relate to Convertible Securities, the minimum aggregate amount of 
     additional consideration, if any, payable upon the issue or sale of 
     such Convertible Securities and upon the conversion or exchange 
     thereof, by (ii) the total maximum number of shares of Common Stock 
     issuable upon the exercise of such rights or options or upon the 
     conversion or exchange of all such Convertible Securities issuable upon 
     the exercise of such rights or options) shall be less than the Exercise 
     Price in effect as of the date of granting such rights or options, then 
     the total maximum number of shares 

                                       67

<PAGE>

     of Common Stock issuable upon the exercise of such rights or options or 
     upon conversion or exchange of all such Convertible Securities issuable 
     upon the exercise of such rights or options shall be deemed to be 
     Outstanding as of the date of the granting of such rights or options 
     and to have been issued for such price per share, with the effect on 
     the Exercise Price as specified in Section 4.2.1 hereof.  Except as 
     provided herein, no further adjustment of the Exercise Price shall be 
     made upon the actual issuance of such Common Stock or of such 
     Convertible Securities upon exercise of such rights or options or upon 
     the actual issuance of such Common Stock upon conversion or exchange 
     of such Convertible Securities.

        4.2.4     If: (i) the purchase price provided for in any right 
     or option, (ii) the additional consideration, if any, payable upon the 
     conversion or exchange of any Convertible Securities or (iii) the rate 
     at which any Convertible Securities are convertible into or 
     exchangeable for Common Stock shall be decreased (other than under or 
     by reason of provisions designed to protect against dilution), the 
     Exercise Price then in effect shall be decreased to the Exercise Price 
     that would have been in effect had such rights, options or Convertible 
     Securities provided for such changed purchase price, additional 
     consideration or conversion rate at the time initially issued.
     
        4.2.5     In case at any time Common Stock or Convertible 
     Securities or any rights or options to purchase Common Stock or 
     Convertible Securities shall be issued or sold for cash, the total 
     amount of cash consideration shall be deemed to be the amount received 
     by the Company. If at any time any Common Stock, Convertible 
     Securities or any rights or options to purchase any such Common Stock 
     or Convertible Securities shall be issued or sold for consideration 
     other than cash, the amount of the consideration other than cash 
     received by the Company shall be deemed to be the fair value of such 
     consideration, as determined reasonably and in good faith by the Board 
     of Directors of the Company. If at any time any Common Stock, 
     Convertible Securities or any rights or options to purchase any Common 
     Stock or Convertible Securities shall be issued in connection with any 
     merger or consolidation in which the Company is the surviving 
     corporation, the amount of consideration received therefor shall be 
     deemed to be the fair value, as determined reasonably and in good 
     faith by the Board of Directors of the Company, of such portion of the 
     assets and business of the non-surviving corporation as such Board of 
     Directors may determine to be attributable to such Common Stock, 
     Convertible Securities, rights or options, as the case may be. In case 
     at any time any rights or options to purchase any shares of Common 
     Stock or Convertible Securities shall be issued in connection with the 
     issuance and sale of other securities of the Company, together 
     consisting of one integral transaction in which no consideration is 
     allocated to such rights or options by the parties, such rights or 
     options shall be deemed to have been issued without consideration. 

        4.2.6     In the case the Company shall take a record of the 
     Holders of its Common Stock for the purpose of entitling them (i) to 
     receive a dividend or other distribution payable in Common Stock or 
     Convertible Securities, or (ii) to subscribe for or purchase Common 
     Stock or Convertible Securities, then such record date shall be deemed 
     to be the date of the issuance or sale of the Common Stock or 
     Convertible Securities deemed to have been issued or sold as a result 
     of the declaration of such dividend or the making of such other 
     distribution or the date of the granting of such right of subscription 
     or purchase, as the case may be.

        4.2.7     The number of shares of Common Stock outstanding at 
     any given time shall not include shares owned directly by the Company 
     in treasury, and the disposition of any such shares shall be 
     considered an issuance or sale of Common Stock.
     
   4.3  STOCK DIVIDENDS.  In case the Company shall declare a dividend 
or make any other distribution upon any shares of the Company, payable 
in Common Stock or Convertible Securities, any Common Stock or 
Convertible Securities, as the case may be, issuable in payment of 
such dividend or 

                                       68

<PAGE>

distribution shall be deemed to have been issued or sold without 
consideration.

   4.4  STOCK SPLITS AND REVERSE SPLITS.  In the event that the 
Company shall at any time subdivide its outstanding shares of Common 
Stock into a greater number of shares, the Exercise Price in effect 
immediately prior to such subdivision shall be proportionately reduced 
and the number of Warrant Shares purchasable pursuant to this Warrant 
immediately prior to such subdivision shall be proportionately 
increased, and conversely, in the event that the outstanding shares of 
Common Stock shall at any time be combined into a smaller number of 
shares, the Exercise Price in effect immediately prior to such 
combination shall be proportionately increased and the number of 
Warrant Shares purchasable upon the exercise of this Warrant 
immediately prior to such combination shall be proportionately 
reduced.  Except as provided in this Section 4.4, no adjustment in the 
Exercise Price and no change in the number of Warrant Shares shall be 
made under this Article IV as a result of or by reason of any such 
subdivision or combination.

   4.5  REORGANIZATIONS AND ASSET SALES.  If any capital 
reorganization or reclassification of the capital stock of the 
Company, or any consolidation, merger or share exchange of the Company 
with another Person, or the sale, transfer or other disposition of all 
or substantially all of its assets to another Person shall be effected 
in such a way that Holders of Common Stock shall be entitled to 
receive capital stock, securities or assets with respect to or in 
exchange for their shares, then the following provisions shall apply:

         4.5.1     As a condition of such reorganization, 
     reclassification, consolidation, merger, share exchange, sale, 
     transfer or other disposition, lawful and adequate provisions shall be 
     made whereby the Holder shall thereafter have the right to purchase 
     and receive upon the terns and conditions specified in these Warrants 
     and in lieu of the Warrant Shares immediately theretofore receivable 
     upon the exercise of the rights represented hereby, such shares of 
     capital stock, securities or assets as may be issued or payable with 
     respect to or in exchange for a number of outstanding shares of such 
     Common Stock equal to the number of Warrant Shares immediately 
     theretofore so receivable had such reorganization, reclassification, 
     consolidation, merger, share exchange or sale not taken place, and in 
     any such case appropriate provision reasonably satisfactory to such 
     Holder shall be made with respect to the rights and interests of such 
     Holder to the end that the provisions hereof (including, without 
     limitation, provisions for adjustments of the Exercise Price and of 
     the number of Warrant Shares receivable upon the exercise) shall 
     thereafter be applicable, as nearly as possible, in relation to any 
     shares of capital stock, securities or assets hereafter deliverable 
     upon the exercise of Warrants.
     
        4.5.2     In the event of a merger, share exchange or 
     consolidation of the Company with or into another Person as a result 
     of which a number of shares of common stock or its equivalent of the 
     successor Person greater or lesser than the number of shares of Common 
     Stock outstanding immediately prior to such merger, share exchange or 
     consolidation are issuable to Holders of Common Stock, then the 
     Exercise Price in effect immediately prior to such merger, share 
     exchange or consolidation shall be adjusted in the same manner as 
     though there were a subdivision or combination of the outstanding 
     shares of Common Stock.

        4.5.3     The Company shall not effect any such consolidation, 
     merger, share exchange, sale, transfer or other disposition unless 
     prior to or simultaneously with the consummation thereof the successor 
     Person (if other than the Company) resulting from such consolidation, 
     share exchange or merger or the Person purchasing or otherwise 
     acquiring such assets shall have assumed by written instrument 
     executed and mailed or delivered to the Holder hereof at the last 
     address of such Holder appearing on the books of the Company the 
     obligation to deliver to such Holder such shares of capital stock, 
     securities or assets as, in accordance with the foregoing provisions, 
     such Holder may be entitled to receive, and all other liabilities and 
     obligations of the Company hereunder. Upon written request by the 
     Holder hereof, such successor person will issue a new Warrant revised 
     to reflect the modifications in this Warrant effected pursuant to this 
     Section.

                                       69

<PAGE>

        4.5.4     If a purchase, tender or exchange offer is made to 
     and accepted by the holders of 50% or more of the outstanding shares 
     of Common Stock, the Company shall not effect any consolidation, 
     merger, share exchange or sale, transfer or other disposition of all 
     or substantially all of the Company's assets with the Person having 
     made such offer or with any affiliate of such Person, unless prior to 
     the consummation of such consolidation, merger, share exchange, sale, 
     transfer or other disposition the Holder hereof shall have been given 
     a reasonable opportunity to then elect to receive upon the exercise of 
     the Warrants either the capital stock, securities or assets then 
     issuable with respect to the Common Stock or the capital stock, 
     securities or assets, or the equivalent, issued to previous holders of 
     the Common Stock in accordance with such offer.

        4.6  ADJUSTMENT FOR ASSET DISTRIBUTION.  If the Company 
declares a dividend or other distribution payable to all holders of 
shares of Common Stock in evidences of indebtedness of the Company or 
other assets of the Company (including, cash (other than regular cash 
dividends declared by the Board of Directors), capital stock (other 
than Common Stock, Convertible Securities or options or rights 
thereto) or other property), the Exercise Price in effect immediately 
prior to such declaration of such dividend or other distribution shall 
be reduced by an amount equal to the amount of such dividend or 
distribution payable per share of Common Stock, in the case of a cash 
dividend or distribution, or by the fair value of such dividend or 
distribution per share of Common Stock (as reasonably determined in 
good faith by the Board of Directors of the Company), in the case of 
any other dividend or distribution. Such reduction shall be made 
whenever any such dividend or distribution is made and shall be 
effective as of the date as of which a record is taken for purpose of 
such dividend or distribution or, if a record is not taken, the date 
as of which Holders of record of Common Stock entitled to such 
dividend or distribution are determined.

   4.7  DE MINIMIS ADJUSTMENTS.  No adjustment in the number of shares of Common
Stock purchasable hereunder shall be required unless such adjustment would
require an increase or decrease of at least one share of Common Stock
purchasable upon an exercise of each Warrant and no adjustment in the Exercise
Price shall be required unless such adjustment would require an increase or
decrease of at least $0.01 in the Exercise Price; provided, however, that any
adjustments that are not required to be made shall be carried forward and taken
into account in any subsequent adjustment. All calculations shall be made to the
nearest full share or nearest one hundredth of a dollar, as applicable.

   4.8  NOTICE OF ADJUSTMENT.  Whenever the Exercise Price or the 
number of Warrant Shares issuable upon the exercise of the Warrants 
shall be adjusted as herein provided, or the rights of the Holder 
hereof shall change by reason of other events specified herein, the 
Company shall compute the adjusted Exercise Price and the adjusted 
number of Warrant Shares in accordance with the provisions hereof and 
shall prepare an Officer's Certificate setting forth the adjusted 
Exercise Price and the adjusted number of Warrant Shares issuable upon 
the exercise of the Warrants or specifying the other shares of stock, 
securities or assets receivable as a result of such change in rights, 
and showing in reasonable detail the facts and calculations upon which 
such adjustments or other changes are based, and shall obtain an 
opinion of the Company's independent accountants as to the correctness 
of such adjustments and calculations and to the effect that such 
adjustments and calculations have been made in accordance with the 
terms hereof.  The Company shall cause to be mailed to the Holder 
hereof copies of such Officer's Certificate together with a notice 
stating that the Exercise Price and the number of Warrant Shares 
purchasable upon exercise of the Warrants have been adjusted and 
setting forth the adjusted Exercise Price and the adjusted number of 
Warrant Shares purchasable upon the exercise of the Warrants.

   4.9  NOTIFICATIONS TO HOLDERS.  In case at any time the Company 
proposes:

       (i)  to declare any dividend upon its Common Stock payable in 
   capital stock or make any special dividend or other distribution 
   (other than cash dividends) to the Holders 

                                       70

<PAGE>

of its Common Stock;

      (ii) to offer for subscription pro rata to all of the Holders of 
   its Common Stock any additional shares of capital stock of any class 
   or other rights;

     (iii) to effect any capital reorganization, or reclassification 
   of the capital stock of the Company, or consolidation, merger or share 
   exchange of the Company with another Person, or sale, transfer or 
   other disposition of all or substantially all of its assets; or

      (iv) to effect a voluntary or involuntary dissolution, 
   liquidation or winding up of the Company,

then, in any one or more of such cases, the Company shall give the 
Holder hereof (a) at least 10 days (but not more than 90 days) prior 
written notice of the date on which the books of the Company shall 
close or a record shall be taken for such dividend, distribution or 
subscription rights or for determining rights to vote in respect of 
any such issuance, reorganization, reclassification, consolidation, 
merger, share exchange, sale, transfer, disposition, dissolution, 
liquidation or winding up, and (b) in the case of any such issuance, 
reorganization, reclassification, consolidation, merger, share 
exchange, sale, transfer, disposition, dissolution, liquidation or 
winding up, at least 10 days (but not more than 90 days) prior written 
notice of the date when the same shall take place. Such notice in 
accordance with the foregoing clause (a) shall also specify, in the 
case of any such dividend, distribution or subscription rights, the 
date on which the Holders of Common Stock shall be entitled thereto, 
and such notice in accordance with the foregoing clause (b) shall also 
specify the date on which the Holders of Common Stock shall be 
entitled to exchange their Common Stock, as the case may be, for 
securities or other property deliverable upon such reorganization, 
reclassification, consolidation, merger, share exchange, sale, 
transfer, disposition, dissolution, liquidation or winding up, as the 
case may be.

   4.10 COMPANY TO PREVENT DILUTION.

        4.10.1    If any event or condition occurs as to which other 
     provisions of this Article are not strictly applicable or if strictly 
     applicable would not fairly protect the exercise or purchase rights of 
     the Warrants evidenced hereby in accordance with the essential intent 
     and principles of such provisions, or that might materially and 
     adversely affect the exercise or purchase rights of the Holder hereof 
     under any provisions of this Warrant, then the Company shall make such 
     adjustments in the application of such provisions, in accordance with 
     such essential intent and principles, so as to protect such exercise and 
     purchase rights as aforesaid, and any adjustments necessary with respect 
     to the Exercise Price and the number of Warrant Shares purchasable 
     hereunder so as to preserve the rights of the Holder hereunder. In no 
     event shall any such adjustment have the effect of increasing the 
     Exercise Price as otherwise determined pursuant to this Article except 
     in the event of a combination of shares of the type contemplated in 
     Section 4.4 hereof, and then, in no event, to an amount greater than the 
     Exercise Price as adjusted pursuant to Section 4.4 hereof.

        4.10.2    In furtherance of the anti-dilution protections 
     afforded Holder pursuant to this Article IV, in the event of any 
     dilutive event described in this Article IV as a result of the 
     settlement of any of the Company's existing or future litigation 
     matters (including, but not limited to, Radman et al v. Photran 
     Corporation, David E. Stevenson v. Photran Corporation and MIK Physics 
     Incorporated v. Photran Corporation), not only will Holder be afforded 
     an adjustment to the Exercise Price as set forth in Article IV, 
     Section 4.2, but Holder shall also be entitled to the number of shares 
     issuable upon exercise of this Warrant increased by the greater of (i) 
     the ratio which the Exercise Price immediately before such issuance 
     bears to the adjusted Exercise Price immediately after such issuance 
     and (ii) the number of shares that would be equal to the same 
     percentage ownership by the Holder of the Company after giving effect 
     to the dilutive event as existed before the occurrence of 
     
                                       71

<PAGE>


     the dilutive event.

                             ARTICLE V

                          MISCELLANEOUS

   5.1  ENTIRE AGREEMENT.  This Warrant, the Agreement and the 
Registration Rights Agreement contain the entire agreement between the 
Holder hereof and the Company with respect to the Warrant Shares 
purchasable upon exercise hereof and the related transactions and 
supersede all prior arrangements or understandings with respect 
thereto.

   5.2  GOVERNING LAW.  This Warrant shall be governed by and 
construed in accordance with the laws of the State of Minnesota.

   5.3  WAIVER AND AMENDMENT.  Any term or provision of this Warrant 
may be waived at any time by the party which is entitled to the 
benefits thereof and any term or provision of this Warrant may be 
amended or supplemented at any time by agreement of the Holder hereof 
and the Company, except that any waiver of any term or condition, or 
any amendment or supplementation, of this Warrant shall be in writing. 
A waiver of any breach or failure to enforce any of the terms or 
conditions of this Warrant shall not in any way affect, limit or waive 
a party's rights hereunder at any time to enforce strict compliance 
thereafter with every term or condition of this Warrant.

   5.4  ILLEGALITY.  In the event that any one or more of the 
provisions contained in this Warrant shall be determined to be 
invalid, illegal or unenforceable in any respect for any reason, the 
validity, legality and enforceability of any such provision in any 
other respect and the remaining provisions of this Warrant shall not, 
at the election of the party for whom the benefit of the provision 
exists, be in any way impaired.

   5.5  COPY OF WARRANT.  A copy of this Warrant shall be filed among 
the records of the Company.

   5.6  NOTICE.  Any notice or other document required or permitted to 
be given or delivered to the Holder hereof shall be in writing and 
delivered at, or sent by certified or registered mail to such Holder 
at, the last address shown on the books of the Company maintained at 
the Warrant Office for the registration of this Warrant or at any more 
recent address of which the Holder hereof shall have notified the 
Company in writing. Any notice or other document required or permitted 
to be given or delivered to the Company, other than such notice or 
documents required to be delivered to the Warrant Office, shall be 
delivered at, or sent by certified or registered mail to, the offices 
of the Company at 21875 Grenada Avenue, Lakeville, Minnesota  55044, 
or such other address within the continental United States of America 
as shall have been furnished by the Company to the Holder of this 
Warrant.

   5.7  LIMITATION OF LIABILITY; NOT SHAREHOLDERS.  No provision of 
this Warrant shall be construed as conferring upon the Holder hereof 
the right to vote, consent, receive dividends or receive notices 
(other than as herein expressly provided) in respect of meetings of 
shareholders for the election of directors of the Company or any other 
matter whatsoever as a shareholder of the Company. No provision 
hereof, in the absence of affirmative action by the Holder hereof to 
purchase shares of Common Stock, and no mere enumeration herein of the 
rights or privileges of the Holder hereof, shall give rise to any 
liability of such Holder for the purchase price of any shares of 
Common Stock or as a shareholder of the Company, whether such 
liability is asserted by the Company or by creditors of the Company.

   5.8  EXCHANGE, LOSS, DESTRUCTION, ETC. OF WARRANT.  Upon receipt of 
evidence reasonably satisfactory to the Company of the loss, theft, 
mutilation or destruction of this Warrant, and in the case of 

                                       72

<PAGE>

any such loss, theft or destruction upon delivery of a bond of 
indemnity or such other security in such form and amount as shall be 
reasonably satisfactory to the Company, or in the event of such 
mutilation upon surrender and cancellation of this Warrant, the 
Company will make and deliver a new Warrant of like tenor, in lieu of 
such lost, stolen, destroyed or mutilated Warrant. Any Warrant issued 
under the provisions of this Section 5.8 in lieu of any Warrant 
alleged to be lost, destroyed or stolen, or in lieu of any mutilated 
Warrant, shall constitute an original contractual obligation on the 
part of the Company. This Warrant shall be promptly canceled by the 
Company upon the surrender hereof in connection with any exchange or 
replacement. The Company shall pay all taxes (other than securities 
transfer taxes or income taxes) and all other expenses and charges 
payable in connection with the preparation, execution and delivery of 
Warrants pursuant to this Section 5.8.

   5.9  REGISTRATION RIGHTS.  The Warrant Shares shall be entitled to such
registration rights under the Securities Act and under applicable state
securities laws as are specified in the Registration Rights Agreement.

   5.10 HEADINGS.  The Article and Section and other headings herein 
are for convenience only and are not a part of this Warrant and shall 
not affect the interpretation hereof.



















                                       73

<PAGE>


   IN WITNESS WHEREOF, the Company has caused this Warrant to be signed in its
name.

Dated: February 9, 1998.


                                     PHOTRAN CORPORATION


                                      By: /s/ Paul T. Fink
                                          ----------------------------
                                          Paul T. Fink, CEO
                                          ----------------------------








                                       74

<PAGE>


                    SUBSCRIPTION NOTICE

   The undersigned, the holder of the foregoing Warrant, hereby elects 
to exercise purchase rights represented thereby for, and to purchase 
thereunder, _______ shares of the Common Stock covered by such 
Warrant, and herewith makes payment in full for such shares, and 
requests (a) that certificates for such shares (and any other 
securities or other property issuable upon such exercise) be issued in 
the name of, and delivered to ________________, and (b) if such shares 
shall not include all of the shares issuable as provided in such 
Warrant, that a new Warrant of like tenor and date for the balance of 
the shares issuable thereunder be delivered to the undersigned.

Date:


                                  ------------------------------------









                                       75