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                                                                   EXHIBIT 10.18

IPG PHOTONICS CORPORATION PURCHASE AND SALE AGREEMENT No. 1/99
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This Purchase Agreement ("Agreement") is entered into by IPG Photonics
Corporation ("IPG"), representing the IPG Group of companies, and SDL
Incorporated ("SDL") in respect of a firm order for                     of
products as specified hereunder, on the following terms and conditions.

1.  PURCHASE OF MATERIALS.

    1.1 This Agreement constitutes a firm purchase and sale obligation between
        the parties hereto. IPG shall purchase and SDL shall sell the products
        specified as per the attached Exhibit B ("Products") in the numbers and
        of the specifications therein, and at the prices specified in Exhibit C.
        The initial delivery schedule in Exhibit A may be revised by IPG in
        accordance with the Release Order procedures described in Article 4
        ("Release Orders") if IPG's requirements change.

        If the numbers of units agreed by IPG for delivery, in accordance with
        the release procedure, falls short by    in any three (3) month period,
        in comparison with the delivery schedule specified in Exhibit A, or if
        the committed    for delivery during the 18 months term of this
        Agreement are no longer a reasonable estimate, SDL reserves the right to
        adjust the prices in negotiation with IPG, provided that the shortfall
        is not the result of SDL's inability to deliver the Products as per the
        Release
        Orders.

        Such price adjustment will be based upon, but not limited to, an
        analysis of the number of units of Products released to date, the
        remaining Term of this Agreement and the rolling horizon forecast for
        the remaining Term of this Agreement.

        IPG acknowledges that SDL's prices contained in Exhibit C are based on
        IPG's commitment to purchase    within the eighteen (18) months' Term of
        this Agreement.

2.  PRICES AND INVOICES.

    2.1 The prices for the Products are listed in Exhibit C in U.S. currency,
        unless otherwise stated, and shall remain in effect during the Term of
        this Agreement as defined in Article 19.1 of the Agreement ("Term of
        this Agreement"). If during the Term price changes are put into effect
        by mutual agreement of IPG and SDL, such prices shall apply to all
        Release Orders issued by IPG after the effective date(s) of such price
        change(s).
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    2.2 All invoices in respect of supplies to IPG from SDL are due for payment
        thirty (30) days from the date of invoices, provided that:

        (a) the goods ("Products") are received by IPG in sound condition;

        (b) the goods ("Products") conform to the Release Orders and the agreed
            specification.

    2.3 Freight charges and all applicable taxes and duties in respect of
        supplies shall be paid directly by IPG. Notwithstanding the foregoing,
        if appropriate SDL reserves the right to collect all applicable taxes if
        valid tax exemption certificates are not furnished by IPG to SDL.

    2.4 IPG may deduct from SDL's outstanding invoices any monies owed to IPG by
        SDL as a result of transactions under this Agreement.

3.  SHIPMENT AND DELIVERY.

    3.1 Each delivery of Products shall be initiated by a written or electronic
        Release Order issued to SDL by IPG. Each Release Order shall specify:
        (i) the quantity of Products in numbers, (ii) the unit price, (iii) the
        required shipment dates, and (iv) the preferred common carrier or
        freight forwarder. SDL shall confirm receipt and commit to the shipment
        dates ("Commitment Date") of the Release Order within ten (10) working
        days from the date thereof. If there is an error, inconsistency with the
        terms of this Agreement or a problem in committing to the required
        shipment dates, SDL and IPG agree to negotiate in good faith a mutually
        acceptable solution for the Release Order in question.

    3.2 A Release Order shall be deemed to have been placed as of the issue date
        thereof. IPG shall not be liable for any costs related to or payments
        for:

        (a) Products not subject to a Release Order from IPG;

        (b) Products received by IPG but not conforming to the Release Order or
            to the agreed specification.

    3.3 All deliveries shall be made complete as per the Release Orders. SDL
        shall, within twenty-four (24) hours of SDL's discovery of any potential
        failure to ship the specified quantity of Products by the Commitment
        Date, give IPG both an oral notification, followed by either a written
        or electronic communication of any such potential failure. Should only a
        portion of the Products be available for shipment by the Commitment
        Date, SDL shall ship the available Products unless directed in writing
        by IPG to rechedule shipment.

    3.4 If SDL ships any Product by a method other than as specified in the
        corresponding Release Order, SDL shall pay any resulting increase in the
        cost of freight incurred over the cost of freight which would have been
        incurred had SDL complied with IPG's shipping instructions.

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    3.5 If SDL fails to make a timely shipment by the Commitment Date, the
        Products affected shall be shipped by air transportation or other
        expedient means. SDL shall pay for any resulting increase in the freight
        cost over that which IPG would have been required to pay by the
        specified method of transportation.

    3.6 If SDL ships more Products than as per the Release Order, the numbers
        over-shipped may, at IPG's discretion, either be kept by IPG for credit
        against future Release Orders or returned to SDL pursuant to Article 6.
        If IPG elects to retain the Products for credit against future Release
        Orders, SDL shall be authorized to issue an invoice to IPG for such
        Products, for which payment shall be due thirty (30) days from the
        agreed delivery date of the subsequent Release Order and in accordance
        with Article 2.2. However, in no case shall payment be delayed for
        greater than sixty (60) days from the date of invoice.

    3.7 SDL shall obtain IPG's approval before making any shipment more than
        five (5) working days prior to the Commitment Date specified in the
        Release Order. If SDL ships more than five (5) working days in advance
        of such Commitment Date without IPG's approval, IPG may at its option
        either return the Products pursuant to Article 6 or make payment in
        accordance with the delivery date as per the Release Order and in
        accordance with Article 2.2. However, in no case shall payment be
        delayed for greater than sixty (60) days from the date of invoice.

    3.8 Failure to deliver at least      of the specified quantities in a
              month period according to the Release Order (a "Shortfall") shall
        constitute a breach of this Agreement. In such an event, IPG will advise
        SDL in writing providing details of the Shortfall in delivery and will
        allow SDL thirty (30) days to make good the Shortfall. Failure by SDL to
        make good the Shortfall within such thirty (30) day cure period shall
        constitute a material breach of the Agreement. In such an event, the
        parties agree to meet and negotiate in good faith a recovery plan for
        the delivery schedule.

    3.9 Shipment shall be F.O.B. SDL's plant or warehouse in the United States.
        Upon shipment by SDL i.e. upon delivery of the Products to the common
        carrier of freight forwarder specified by IPG in the Release Order,
        title to the Products and the risk of loss or damage shall pass from SDL
        to IPG, subject to the provisions of Article 3.10.

    3.10 SDL shall preserve, package, handle and pack the Products adequately to
        protect the Products from loss or damage, in conformity with sound
        commercial practice. SDL shall be responsible for any loss or damage due
        to its failure to adequately preserve, package, handle or pack the
        Products. In such an event, IPG shall not be required to pursue any
        claims for such loss or damage against the common carrier involved.

    3.11 Each delivery of Products to IPG shall include a packing list, which
        shall contain at least the following information:

        (a) The Release Order number;

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        (b) the SDL part numbers;

        (c) The quantity of Products shipped; and

        (d) The date of shipment.

4.  RELEASE PROCEDURE.

    4.1 IPG shall issue Release Orders for Product deliveries in accordance with
        an 18-month rolling horizon forecast consisting of three time zones:
        Fixed, Firm and Planning. The Fixed zone shall comprise at all times the
        first three months of the current balance of this Agreement's Term,
        initially months 1 through 3. The Firm zone shall be the three month
        period following the Fixed zone, initially months 4-6. The Planning zone
        shall be the remaining months in the Term, initially months 7-18. IPG
        shall provide SDL a written update of the rolling horizon forecast
        during the first week of each month of the Agreement Term, showing by
        month the quantities forecast for each of the zones. The initial rolling
        horizon forecast shall be the delivery schedule contained in Exhibit A
        attached hereto.

        (a) Product quantities for delivery in the Fixed zone are
            and IPG shall issue Release Orders for such quantities of the
            Product when a particular month first enters the Fixed zone, which
            is          prior to shipment.

        (b) Product quantities for delivery in the Firm zone may be varied by up
            to + or -     prior to a particular month entering the Fixed zone.
            Such percentage variance shall be calculated by comparing the
            quantity specified for that month upon entering the Firm zone with
            that same month's quantity upon entering the Fixed zone.

        (c) Product quantities for delivery in the Planning zone are
            and may be       subject to the total    order commitment
            described in Article 1.1.

    4.2 Changes to Product deliveries within the Fixed zone or in excess of the
        allowable variance within the Firm zone as specified in Article 4.1 are
        not permitted except by mutual agreement.

5.  QUALITY PROGRAM, INSPECTION AND WARRANTY.

    5.1 SDL shall maintain an objective quality program for all Products
        supplied pursuant to this Agreement. SDL's program shall be in
        accordance with the current and updated version of SDL's Quality Policy
        during the Term of this Agreement. SDL shall, upon IPG's request,
        provide to IPG copies of SDL's policy

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        and procedures and SDL agrees to consider IPG's requests for amendments
        to such policy and procedures.

    5.2 IPG shall have the right to inspect, at a mutually agreed time, at SDL's
        plant, both Products and nonproprietary testing areas for the Products,
        Any such inspection of Products shall be prior to shipment; testing
        areas may be inspected at any time during the Term of this Agreement.
        IPG has the right to such inspection provided such inspection is
        reasonable and relevant to this Agreement, including without limitation
        to ensure SDL's compliance with the specified and applicable quality
        requirements. SDL shall provide access for IPG to SDL's facilities and
        services as may be reasonably required by IPG in performing any such
        inspection. Acceptance by IPG of any Products inspected pursuant to this
        Article 5.2 shall be final only after inspection, pursuant to Article 7,
        of the Products by IPG at its own works after delivery.

    5.3 SDL warrants that all Products shall be free from defects in workmanship
        and materials. This warranty does not apply to Products which have
        failed, become defective or unworkable due to abuse, mishandling,
        misuse, alteration, negligence, improper installation, use which is not
        in accordance with the information and precautions described in the
        applicable operating manual, or other causes beyond SDL's control. This
        warranty does not apply to (i) any Products or components not
        manufactured by SDL or (ii) any aspect of the Products based on IPG's
        specification, if applicable, unless SDL has reviewed and approved such
        specification in writing.

    5.4 The warranty specified in Article 5.3 shall:

        (a) Survive any inspection, delivery, acceptance, or payment by IPG; and

        (b) Be in effect for        following the date of shipment of
            the Products to IPG; or

        (c) In the case of Products under warranty that are replaced or
            reworked, be in effect for the remaining unexpired portion of the
            original warranty period applicable to the replaced or reworked
            Product, excluding the time period between SDL's receipt of said
            Product and its return to IPG.

    5.5 THE FOREGOING WARRANTY IS EXCLUSIVE AND IS IN LIEU OF ALL OTHER
        WARRANTIES, WHETHER EXPRESSED OR IMPLIED, AS TO THE PRODUCTS, INCLUDING
        ANY IMPLIED WARRANTY OF MARKETABILITY OR FITNESS FOR A PARTICULAR
        PURPOSE. IPG'S SOLE AND EXCLUSIVE REMEDY SHALL BE SDL'S OBLIGATION TO
        REPLACE THE PRODUCT OR GIVE A CREDIT OR REFUND AS SET FORTH IN ARTICLES
        6 and 7. IN NO CASE WILL SDL'S AGGREGATE LIABILITY TO IPG UNDER THIS
        ARTICLE 5.5 BE GREATER THAN THE PURCHASE PRICE ACTUALLY PAID BY IPG TO
        SDL FOR THE PRODUCTS WHICH ARE THE SUBJECT OF IPG'S CLAIM.

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6.  RETURN OF PRODUCTS.

    6.1 All Products returned by IPG to SDL, including Noncomplying Products
        defined in Article 7.1 below, shall be accompanied by a Return Materials
        Authorization ("RMA"). Unless further verification is reasonably
        required by SDL, SDL shall supply an RMA within three (3) working days
        of IPG's request for the return of suspected Noncomplying Products and
        for all other Product returns. If further verification is so required,
        the RMA shall be supplied by SDL within five (5) working days of receipt
        of the appropriate verification from IPG. With the return of any
        suspected Noncomplying Product under this Article, IPG will specify, in
        writing, the reasons for non-compliance with the return.

    6.2 All suspected Noncomplying Products shall be returned by IPG freight
        prepaid to SDL's facility. All overshipments, and early shipments
        returned by IPG to SDL, and all replacement or reworked Products shipped
        by SDL to IPG to replace Noncomplying Products, shall be at SDL's risk
        and expense, including transportation charges to IPG.

7.  INSPECTION, ACCEPTANCE AND NONCOMPLYING PRODUCTS.

    7.1 All Products shall be subject to acceptance inspection and testing by
        IPG upon delivery. Unless IPG notifies SDL in writing of rejection by
        IPG within fifteen (15) working days of receipt of the Product, such
        received Product shall be deemed to be provisionally accepted. However,
        IPG reserves the right to conduct lifetime tests of the Products as
        described in the agreed specification to ensure compliance and unless
        IPG notifies SDL in writing within sixty (60) working days of receipt of
        the Product of any such lifetime test failures, such received Product
        shall be deemed to be accepted.

        If any Product is deemed to be defective or otherwise not in conformity
        with the specification of this Agreement by IPG, IPG shall return the
        suspected Noncomplying Product in accordance with Article 6. If SDL,
        after SDL's inspection of the suspect Noncomplying Product, concurs that
        such Product is not in conformity with the specification and, therefore,
        deemed a "Noncomplying Product", SDL may elect in its sole discretion,
        to:

        (a) Replace or rework at SDL's expense the Noncomplying Product; or

        (b) Refund any payment made to SDL for the Noncomplying Product within
            thirty (30) days from the date of return of the Noncomplying
            Product.

    7.2 SDL shall, if SDL selects the alternative in Article 7.1(a), return the
        replacement or reworked Product as soon as possible but in any event
        prior to any further shipment of new units.

    7.3 If SDL fails to return the replacement or reworked Product to IPG in a
        timely manner as specified in Article 7.2, IPG may reject the
        Noncomplying Product and refuse acceptance of replacement or reworked
        Product and accept a full refund of

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        the original purchase price of the replacement or reworked Product
        without any deductions by SDL. Any Product refunds pursuant to this
        Article 7.3 or 7.1(b) shall be counted toward IPG's total purchase
        obligation set forth in Article 1.1.

    7.4 SDL shall provide IPG with SDL's elected disposition of any suspect
        Noncomplying Products within thirty (30) working days of receipt of the
        Product at SDL's facility. In the event SDL does not find the suspect
        Noncomplying Product to be in non-compliance with the specification, SDL
        shall return the Product to IPG "as is" with a written report of SDL's
        findings.

    7.5 Upon IPG's request, SDL shall promptly furnish a Corrective Action
        Report on any Noncomplying Product.

8.  PROCESS OR DESIGN CHANGES.

    8.1 Unless otherwise covered in an applicable general specification referred
        to in this Agreement:

        (a) With respect to process changes that do not affect the form, fit or
            function of the Products, no significant process changes shall be
            made or incorporated in Products without the prior written
            notification of IPG;

        (b) With respect to process changes that do affect the form, fit or
            function of the Products, or in the event of the withdrawal of a
            product line, SDL shall provide six (6) months' prior written notice
            to IPG. The form, fit, or function of the Products includes all
            characteristics that affect compliance to the specification
            including all external dimensions. SDL shall discuss changes with
            IPG and as far as practicable changes shall accommodate IPG's
            requirements.

    8.2 In the event that changes to the Products affect its form, fit or
        function, or SDL plans to withdraw a Product from its product line, IPG
        shall have the right to make a last buy of the Product prior to the
        effective date of the change or withdrawal. This last buy option shall
        be a firm non-cancelable order. Shipment dates and quantities under this
        last buy provision will be mutually agreed upon by the parties. IPG will
        be relieved of any further purchase obligation for the specified
        Product.

9.  PATENT INDEMNIFICATION.

    9.1 SDL shall defend, indemnify, and hold harmless IPG and its affiliates,
        and subsidiaries, from and against all legal proceedings in respect of
        any alleged infringement of any Products furnished hereunder of any
        United States patents and against all claims, losses, demands, fees,
        damages, liabilities, costs, expenses, and obligations, which may be
        assessed against IPG on account of such infringement; provided that SDL:

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        (a) shall have reasonable written notice of all claims and/or legal
            proceedings alleging such infringement;

        (b) shall have full opportunity and authority to assume the sole defense
            and settlement of such claims and/or legal proceedings; and

        (c) shall be furnished, upon SDL's request and at SDL's expense, all
            reasonable information and assistance from IPG for such defense.

    9.2 In addition to providing information requested by SDL in Article 9.1(c),
        IPG, at its option, shall have the right to participate fully in any
        such defense at IPG's own expense.

    9.3 If any Product in any such legal proceedings or claim is held to
        constitute an infringement ("Infringing Product"), SDL shall at its
        option and expense:

        (a) Procure for IPG the right to continue using the Infringing Product;

        (b) Replace the Infringing Product with a non-infringing Product of like
            form, fit or function;

        (c) Modify the Infringing Product to be non-infringing; or

        (d) If unable to replace or modify the Infringing Product, remove the
            Infringing Product and refund in full the purchase price paid by IPG
            for the Infringing Product without any deductions by SDL.

    9.4 IPG agrees to indemnify, defend and hold harmless SDL from and against
        all legal proceedings and from all claims, losses, demands, fees,
        damages, liabilities, costs, expenses, and obligations, which may be
        assessed in any legal proceedings alleging that the Product infringes
        any United States patent, and only:

        (a) to the extent any such infringement by the Product is found to arise
            from the adherence to specifications or drawings relating to the
            Product which IPG directs SDL to follow; or

        (b) to the extent any such infringement by the Product is caused by the
            incorporation of the Product into devices.

    9.5 IPG's duty to indemnify is contingent upon SDL:

        (a) providing reasonable written notice of all claims and legal
            proceedings alleging such infringement;

        (b) providing IPG the full opportunity and authority to assume the sole
            defense and settlement of such claims and/or legal proceedings; and

        (c) furnishing upon IPG's request and at IPG's expense, all reasonable
            information and assistance from SDL for such defense. In addition to
            providing information requested by IPG, SDL, at its option, shall
            have the right to participate fully in any such defense at SDL's own
            expense.

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10.    LIMITATION OF LIABILITY.

       10.1   IN NO EVENT WILL SDL BE LIABLE FOR ANY INDIRECT, INCIDENTAL,
              SPECIAL OR CONSEQUENTIAL DAMAGES, INCLUDING BUT NOT LIMITED TO
              LOSS OF ANTICIPATED PROFITS OR BENEFITS, EVEN IF SDL HAS BEEN
              INFORMED OF THE POSSIBILITY IN ADVANCE, ARISING OUT OF THE SALE OF
              PRODUCTS OR IN ANY WAY ARISING OUT OF THIS AGREEMENT. EXCEPT FOR
              WARRANTY OBLIGATIONS UNDER ARTICLE 5.5, IN NO CASE WILL SDL'S
              AGGREGATE LIABILITY TO IPG BE GREATER THAN EITHER THE LESSER OF I)
              THE PURCHASE PRICE ACTUALLY PAID BY IPG TO SDL FOR THE PRODUCTS,
              WHICH ARE THE SUBJECT OF IPG'S CLAIM OR II) ONE MILLION DOLLARS.

11.    GOVERNMENTAL COMPLIANCE.

       11.1   SDL shall comply with all federal, state, local, and foreign laws,
              rules, and regulations applicable to its obligations under this
              Agreement or to Products supplied hereunder.

       11.2   SDL shall furnish to IPG any information reasonably required
              during the Term of this Agreement and a reasonable period
              thereafter to enable IPG to comply with the requirements of any
              federal, state, local, or foreign government agency in its use of
              the Products.

       11.3   Without limiting the obligations under Article 11.1, SDL warrants
              that:

              (a)    SDL shall comply with the requirements of Executive Order
                     11246, the Vocational Rehabilitation Act, and the Vietnam
                     Era Veterans Readjustment Assistance Act;

              (b)    Each chemical substance contained in the Products is on the
                     inventory of chemical substances compiled and published by
                     the Environmental Protection Agency pursuant to the Toxic
                     Substances Control Act;

              (c)    All Products shall be shipped in conformity with government
                     or freight regulations and requirements applicable to
                     chemicals; and

              (d)    All Material Safety Data Sheets required to be provided by
                     SDL for any Product shall be provided to IPG prior to
                     shipment of the corresponding Products and shall be
                     complete and accurate.

12.    FORCE MAJEURE.

       12.1   SDL shall not, subject to the provisions of this Article 12, be
              liable for any delay in performance under this Agreement caused by
              fire, flood, earthquake, explosion, war, strike, embargo,
              governmental regulations, civil or military authority, an act of
              God or any other cause beyond SDL's control excluding SDL's fault
              or

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              negligence (collectively "Delaying Cause"). SDL shall, in the
              event of a Delaying Cause, immediately give notice to IPG of the
              Delaying Cause.

       12.2   In the event of a Delaying Cause, IPG may elect in its sole
              discretion, and as its exclusive remedy hereto, to:

              (a)    Terminate this Agreement if such Delaying Cause is not
                     cured within 120 days of said notice to IPG or any part
                     hereof as to Products not shipped; or

              (b)    Suspend this Agreement in whole or in part for the duration
                     of Delaying Cause, buy similar products elsewhere, and
                     deduct from any quantities specified under this Agreement
                     the quantity so purchased.

       12.3   If IPG selects the alternative specified in Article 12.2(b) for
              any Delaying Cause, IPG may resume performance under this
              Agreement once the Delaying Cause ceases to exist and extend the
              Term up to the length of time the Delaying Cause endured.

       12.4   Unless IPG gives notice of termination pursuant to Article 12.2(a)
              120 days after notice from SDL of the Delaying Cause, IPG shall be
              deemed to have selected alternative 12.2(b).

13.    TERMINATION.

       13.1   If either party commits a material breach of any provision or
              obligations of this Agreement, the injured party may by sixty (60)
              days prior written notice to the other party terminate the whole
              or any part of this Agreement unless:

              (a)    during such notice period the defaulting party shall have
                     remedied any such failure; or

              (b)    if the breach is one which by its nature cannot be fully
                     remedied in the sixty (60) day notice period, the parties
                     shall have negotiated in good faith an additional cure
                     period and the defaulting party shall have remedied any
                     such failure within this extended cure period.

              A "Material Breach" herein is a failure of either party to perform
              any substantive promise or performance under this Agreement when
              due without reasonable cause.

       13.2   This Agreement may be terminated forthwith, at the option of
              either party, upon written notice to the other party upon the
              occurrence of any of the following events with respect to the
              other party:

              (a)    Proceedings under state or federal law, whether voluntary
                     or involuntary, in bankruptcy, insolvency or debtor's
                     relief law by or against such party, which proceedings are
                     not dismissed within sixty (60) days;

              (b)    Appointment, with or without such party's consent, of a
                     receiver or an assignee for the benefit of creditors;

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              (c)    Such party ceases to carry on its business;

              (d)    Such party is liquidated or dissolved.

       13.3   The rights and remedies granted to the parties pursuant to this
              Article 13 are in addition to, and shall not limit or affect, any
              other rights or remedies available to the parties in law or in
              equity.

14.    NOTICES.

       14.1   Any notice given pursuant to this Agreement shall be in writing
              and shall be deemed received as of five (5) working days after
              posting by registered or certified mail, return receipt requested,
              postage prepaid (or upon actual receipt thereof, whichever occurs
              first) to the addresses specified on the signature page of this
              Agreement.

       14.2   Either party may change address for purposes of notice in writing
              to the other party.

15.    COUNTRY OF MANUFACTURE AND DUTY DRAWBACK RIGHTS.

       15.1   Upon IPG's request, SDL shall provide IPG with appropriate
              certification stating the country of origin for the Products,
              sufficient to satisfy the requirements of:

              (a)    The customs authorities of the country of receipt; and

              (b)    Any applicable export licensing regulations, including
                     those of the United States.

       15.2   SDL shall mark each Product (or the Product's container if there
              is no room on the Product) with the country of origin. SDL shall,
              in marking Products, comply with the requirements of the customs
              authorities of the country of receipt.

16.    CONFIDENTIAL INFORMATION.

       16.1   IPG and SDL agree that in pursuance of transactions under this
              Agreement, the parties are likely to become both disclosing
              parties of their own Confidential Information and receiving
              parties of Confidential Information. Any such Confidential
              Information shall be used only for performance under this
              Agreement. As used in this Article 16, the term "Confidential
              Information" shall include, without limitation:

              (a)    All information or data concerning or related to either
                     party's products (including discovery, invention, research,
                     improvement, development, manufacture, or sale of products)
                     or business operations (including sales costs, profits,
                     pricing methods, organizations, employee or customer lists,
                     and processes);

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              (b)    All forecasts for production, support, or service
                     requirements submitted by IPG pursuant to this Agreement.

       16.2   All Confidential Information divulged pursuant to this Agreement
              shall be disclosed in writing marked with a "confidential" or
              "proprietary" or similar legend. If Confidential Information is
              divulged other than in writing, it shall be identified as
              proprietary at the time and shall, within 30 days thereof, be
              confirmed in writing, so marked and transmitted to the receiving
              party.

       16.3   All information so identified or marked shall remain the
              disclosing party's property and will be used by the receiving
              party only for performance under this Agreement unless first
              authorized in writing by the disclosing party. The receiving party
              shall not disclose to any person or entity, other than those
              employees of the receiving party who have a need to know, any
              Confidential Information of the disclosing party, which the
              receiving party may obtain from the disclosing party. The
              receiving party shall maintain all Confidential Information in
              strict confidence. The receiving party shall take all reasonable
              steps to ensure that no unauthorized person or entity has access
              to Confidential Information, and that all authorized persons
              having access to Confidential Information refrain from any
              unauthorized disclosure. Any Confidential Information furnished
              hereunder shall be returned or destroyed when the receiving party
              no longer needs the information for the stated purpose or upon the
              disclosing party's request.

       16.4   The obligation imposed by this Article 16 shall continue in full
              force and effect for a period of five (5) years from the date of
              the disclosure, regardless of whether this Agreement is terminated
              earlier.

       16.5   The provisions of this Article 16 shall not apply to any
              information that:

              (a)    is rightfully known to the receiving party prior to
                     disclosure;

              (b)    is rightfully obtained by the receiving party from any
                     third party without any obligation of confidentiality;

              (c)    is or is made available to the public without restrictions;

              (d)    is disclosed by the receiving party with the prior written
                     approval of the disclosing party;

              (e)    is developed independently by the receiving party without
                     benefit of the information received pursuant to this
                     Agreement; or

              (f)    is disclosed in response to a valid order of the court or
                     authorizing agency of government provided however that
                     notice first be given to the disclosing party so that, if
                     appropriate, the disclosing party may seek protection.

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17.    ASSIGNMENT.

       17.1   Except as provided in this Article, neither IPG nor SDL shall
              assign this Agreement or any right or interest under this
              Agreement, nor delegate any duties or assign any rights or claims
              under this Agreement to any third party without the other party's
              prior written consent. Any such attempted delegation or assignment
              shall be void and ineffective. Either party has the right to
              assign this Agreement in whole or in part at any time and without
              the other party's consent to any corporate parent, or to any
              present or future affiliate or subsidiary of the party.

18.    PRECEDENCE.

       18.1   This Agreement takes precedence over either party's additional or
              different terms and conditions, to which objection is hereby made
              by the parties hereto. Acceptance by the parties of a contract to
              purchase and supply the Products is limited to the terms and
              conditions of this Agreement.

       18.2   This Agreement comprises the entire understanding between the
              parties and supersedes any previous communications,
              representations, or agreements, whether oral or written. No
              modification of this Agreement shall be binding on either party
              unless in writing and signed by an authorized representative of
              each party.

       18.3   In the event of any conflict between the provisions of this
              Agreement and any Release Order or Exhibit, the order of
              precedence is as follows:

              (a)    This Agreement;

              (b)    The Exhibits to this Agreement; and

              (c)    Any instructions in a written or electronic Release Order.

19.    TERM.

       19.1   This Agreement shall be effective for the period of eighteen (18)
              months (the "Term of this Agreement") commencing on the date
              specified by the parties as under (the "Commencement Date") unless
              terminated earlier by mutual agreement of the parties or in
              accordance with the provisions of Articles 12 and 13.

              The Commencement Date shall be 01 April 1999, retrospectively.

       19.2   Upon the expiry or termination of this Agreement, the parties may
              mutually agree to extend the terms and conditions contained herein
              to apply to any or all outstanding Release Orders previously
              accepted by SDL and to all Products shipped under such Release
              Orders.

                                      -13-
<PAGE>

       19.3   The provisions of Articles 5.3, 5.4, 5.5, 9, 10, 16, and 19 shall
              survive any expiry or termination of this Agreement.

20.    MISCELLANEOUS.

       20.1   The waiver of any term, condition, or provision of this Agreement
              by IPG or SDL must be in writing and signed by an authorized
              representative of the party providing the waiver. No such waiver
              or delay in enforcement of any right hereunder shall be construed
              as a waiver of any other term, condition, or provision except as
              provided in writing, nor as a waiver of any subsequent breach of
              the same term, condition, or provision.

       20.2   This Agreement shall be interpreted and governed in all respects
              by the laws of the State of California. SDL and IPG hereby consent
              to the jurisdiction and venue of such courts.

       20.3   All references in this Agreement to "days" shall, unless otherwise
              specified herein, mean calendar days.

       20.4   The Article headings used in this Agreement are for convenience of
              reference only. They shall not limit or extend the meaning of any
              provision of this Agreement, and shall not be relevant in
              interpreting any provision of this Agreement.

       20.5   Stenographic, typographical, or clerical errors contained in this
              Agreement are subject to correction by IPG or SDL or contained in
              any Release Order issued thereunder are subject to correction by
              IPG.

       20.6   The parties hereto are independent contractors; under this
              Agreement and no other relationship is intended, including
              partnership, franchise, joint venture, agency, or other business
              organization of any kind or nature whatsoever.

       20.7   If any term or provision of this Agreement is found to be invalid
              under any applicable statute or rule of law, the individual term
              or provision notwithstanding, then the remainder of the Agreement
              shall remain in full force and effect and such term or provision
              shall be deemed omitted.

21.    ARBITRATION.

       21.1   In the event of breach of this Agreement or disputes arising out
              of this, both parties shall make reasonable efforts to reach an
              amicable settlement thereof. If the parties cannot reach an
              amicable settlement within 90 (ninety) days, all disputes arising
              in connection with this Agreement shall be settled under the rules
              of conciliation and arbitration of the American Institution of
              Arbitration by three arbitrators appointed in accordance with the
              said rules. Arbitration shall be held in the United States. The
              findings of the arbitrators shall be final and binding on both
              parties. The language of the proceedings shall be English.

                                      -14-
<PAGE>

22.    EXHIBITS.

       22.1   All Exhibits attached to this Agreement shall be deemed a part of
              this Agreement and incorporated herein by reference. Subject to
              Article 18.3, the term "Agreement" includes the Exhibits listed in
              this Article 22.

       22.2   Terms which are defined in this Agreement and used in any Exhibit
              shall have the same meaning in the Exhibit as in this Agreement.

       22.3   The following Exhibit(s) are hereby made a part of this Agreement:

              EXHIBIT A:  Delivery Schedule
              EXHIBIT B:  Product Specification
              EXHIBIT C:  Product Pricing

APPROVED AND AGREED TO:

--------------------------------------     -------------------------------------
               (SDL)                                       (IPG)

By: /s/ Richard Craig                      By: /s/ Valentin Gapontsev
   -----------------------------------        -----------------------------

Typed Name:  Richard Craig                 Typed Name:  Valentin Gapontsev

Title:  Vice President                     Title:  President & Chief Executive
                                                   Officer

Date Signed:  May 11, 1999                 Date Signed: May 14, 1999
            --------------------------                 --------------------

Address:  80 Rose Orchard Way, San Jose,   Address:  IPG Photonics Corporation,
                                           Galileo

CA 95134-1365                              Park, 660 Main Street, Sturbridge, MA
                                           01566

Attention:   Stephen Eglash                Attention:   David Hardwick

                                      -15-
<PAGE>

                                   Exhibit A

Delivery Schedule

---------------------------------------------------------------
Month                    Quantity                 Cum
---------------------------------------------------------------
Apr 99
---------------------------------------------------------------
May 99
---------------------------------------------------------------
Jun 99
---------------------------------------------------------------
Jul 99
---------------------------------------------------------------
Aug 99
---------------------------------------------------------------
Sept 99
---------------------------------------------------------------
Oct 99
---------------------------------------------------------------
Nov 99
---------------------------------------------------------------
Dec 99
---------------------------------------------------------------
Jan 00
---------------------------------------------------------------
Feb 00
---------------------------------------------------------------
Mar 00
---------------------------------------------------------------
Apr 00
---------------------------------------------------------------
May 00
---------------------------------------------------------------
Jun 00
---------------------------------------------------------------
Jul 00
---------------------------------------------------------------
Aug 00
---------------------------------------------------------------
Sept 00
---------------------------------------------------------------
<PAGE>

 Exhibit B:  PRODUCT SPECIFICATION
<PAGE>

PRODUCT SPECIFICATION
<PAGE>

PRODUCT SPECIFICATION
<PAGE>

Exhibit C               Product Pricing
<PAGE>

                                  AMENDMENT 01
        IPG Photonics Corporation Purchase and Sales Agreement No. 1/99

WHEREAS, IPG and SDL desire to continue the relationship established under this
agreement for the Product(s) by entering into a new purchase period, and;

WHEREAS, IPG is desirous of obtaining substantially increased quantities of
Product(s) over this new purchase period, and;

WHEREAS, SDL is willing to supply IPG the increased demand for Product(s) under
certain terms and conditions;

NOW, THEREFORE, in consideration of the covenants herein, the parties hereto
agree as follows:

I.   Purpose of Amendment:

          This Amendment to IPG Photonics Corporation Purchase and Sales
Agreement No. 1/99 is to extend the period of performance of the Agreement and
establish additional terms and conditions to govern the sale and purchase of
Product(s) for a new commitment by IPG to purchase and take delivery of an
additional                   /1/within a twenty-four month period beginning 01
October 2000 through 30 September 2002 ("Extended Purchase Period").

II.  Article I Purchase of Materials is hereby amended to include the following:

1.2  IPG shall purchase and SDL shall sell the Products for the Extended
     Purchase Period at the prices set forth in Exhibit C and pursuant to the
     delivery schedule in Exhibit A.  The initial delivery schedule in Exhibit A
     may be revised by IPG in accordance with the Release Order procedure
     described in Article 4 if IPG's requirements change.  However IPG
     acknowledges that the unit prices provided for the Product(s) in Exhibit C
     are based on an agreed minimum run rate for total ordered Product.  In the
     event IPG does not place Release Orders for Products to meet the minimum
     total quantities stated below for the specified time periods, IPG shall be
     subject to the following        for the units ordered in such
     time period.  Any incurred       will be invoiced to GP, within
     any such quarter that such a        of Product quantities occurs:

/1/ This total quantity may be adjusted due to product mix allowances
for         quantities as described in Exhibit A.

                                      21
<PAGE>

<TABLE>
<CAPTION>
Period                            Minimum Qty
--------------------------------------------------------------------------------
<S>                             <C>

Any given Quarter               Exhibit A Total
Q4 '00 thru Q3 '01              Quarterly Demand

Any given Quarter               Exhibit A Total
Q4 '00 thru Q3 '02              Quarterly Demand

Where  ATQD = Actual Total Quarterly,
       EATQD = Exhibit A Total Quarterly Demand.
</TABLE>

     If IPG does not place orders to take delivery of at least     of the total
     quantity in any given quarter shown in Exhibit A, IPG shall be deemed in
     material breach of this Agreement in accordance with Article 13 and shall
     be subject to the        and
     below, based upon the sum total of parts up to and including the quarter in
     question.

1.3  Subject always to SDL conforming in all material respects with its
     obligations as set out in this Agreement, then IPG undertakes to purchase
     from SDL a quantity of             units/2/ of Products during the Extended
     Purchase Period.  If upon expiry or termination of the Extended Purchase
     Period of this Agreement the total quantity of Product for which IPG has
     taken delivery is less than             of the total units,/2/ then IPG
     shall in addition to any obligations it may have pursuant to Article 13
     "Termination" pay to SDL a sum calculated as follows:

 a)  For a requested total two-year demand up to              of the two year
     cumulative total in Exhibit A:

 b)  For a requested total two-year demand greater than              units:

     The payment of any such sum shall be in full and final settlement of any
     claim by SDL in respect of its infrastructure investment resulting from
     IPG's failure to take delivery of a quantity of                    of the
     total units/2/ of Product within the Extended Purchase Period.

III.   Article 4 Release Procedure is hereby amended to include the following:

4.1 (d)IPG shall issue Release Orders for Product deliveries in the Extended
     Purchase Period in accordance with a 24-month rolling horizon forecast.
     All time zones shall remain as defined in this Article 4.1.  For purposes
     of the Extended Purchase Period, the Planning zone shall initially be
     months 7-24.  Product quantities forecasted for delivery in the

--------------------------------------
/2/ This total quantity may be adjusted due to prodcut mix allowances
for         quantities as described in Exhibit A.

                                      22
<PAGE>

     various zones of the Extended Purchase Period may be varied as described,
     subject always to the terms of Article I . However, in no event shall IPG's
     forecasted quantity for Product in any given quarter be increased by
     greater than   over that same quarter's initial forecasted demand contained
     in Exhibit A. Additionally, any forecasted demand for total Product may not
     be increased by greater than   over the initial total quantity for Product
     in Exhibit A. In the event IPG requests such increases, SDL reserves the
     right to equitably adjust the                  and
     accordingly.

IV.   Article 13 Termination is hereby amended to include the following:
13.4  In the event of a material breach by IPG, IPG shall remain responsible for
      all penalties. liabilities and other obligations to SDL as of the date of
      termination.

13.5  In the event of a material breach of this Agreement by SDL, SDL shall be
      liable to IPG for a            of                    .
           by SDL to IPG shall constitute full and final settlement between the
      parties for such material breach by SDL.

13.5  In the event IPG cancels a Release Order at any time prior to delivery and
      SDL is not in material breach of this Agreement, IPG shall be liable for:

      IPG shall take delivery of the Fixed zone Product quantities in the event
      of any such cancellation.

V.    Article 16 Confidential Information is hereby amended to include the
      following:

16.6  IPG and SDL agree that this Agreement is considered Confidential
      Information and subject to the provisions of this Article 16. Neither
      party shall without the prior written consent of the other party,
      publicize the fact or contents of this Agreement. In the event that SDL is
      required to release information related to this Agreement, timely consent
      shall be provided by IPG for such release of information.

VI.   Article 19 Term is hereby amended to include the following:
19.1  The term of this Agreement is hereby extended for an additional twenty-
      four (24) month period for a total of forty-two (42) months from the
      Commencement Date.

19.3  The provisions of this Amendment Articles 1.2, 1.3 and 13 shall also
      survive any expiry or termination of this Agreement.

                                      23
<PAGE>

VII.  Exhibits, A - Delivery Schedule, B - Product Specification, and C -Product
      Pricing, are modified as set forth in this Amendment 01 and attached
      hereto.
VIII. The above specified modifications constitute a formal Amendment to the
      Agreement.  Except as herein modified, all other specifications, terms and
      conditions currently applicable to the Agreement remain unchanged.

                                      24
<PAGE>

IN WITNESS WHEREOF, the parties hereto have executed this Amendment 01 by their
respective duly authorized representatives as of the last date set forth below:

Signed for and on behalf of IPG Corp.
<TABLE>
<CAPTION>

<S>                    <C>                                                   <C>
Authorized Signatory:  /s/David Hardwick /s/Valentin P. Gapontsev   Date:     19/05/2000
                       ------------------------------------------             ----------
Name:             David Hardwick/Valentin Gapontsev, Ph.D.                     5/19/2000
Title:            VP & GM/President & GM

Signed for and on behalf of SDL, Inc.

Authorized Signatory:___________________________________________    Date:________________
Name:     Gordon Mitchard
Title:    General Manager
          Industrial Laser Group, SDLI

</TABLE>

                                      25
<PAGE>

                                   Exhibit A

Exhibit A is hereby amended to include the following initial delivery schedule
for the Extended Purchase Period:

                                      26
<PAGE>

                                   Exhibit C

Exhibit C is hereby amended to include the following pricing for the Extended
Purchase Period.

Product Pricing:

                                      27
<PAGE>

                                 AMENDMENT 02
        IPG Photonics Corporation Purchase and Sales Agreement No. 1/99

WHEREAS, IPG and SDL desire to continue the relationship established under this
agreement for the Product(s) by entering into a new purchase period, and;

WHEREAS, IPG  is desirous of obtaining substantially increased quantities of
Product(s) by entering into a new purchase period and;

WHEREAS, SDL is willing to supply IPG the increased demand for Product(s) under
certain terms and conditions;

NOW, THEREFORE in consideration of the covenants herein, the parties hereto
agree as follow:

I.  Purpose of Amendment:

   This Amendment to IPG Photonics Corporation Purchase and Sales Agreement No.
1/99 is to extend the period of performance of the Agreement and establish
additional terms and conditions to govern the sale and purchase of Product(s)
for a new commitment by IPG to purchase and take delivery of an additional
         /1/ within a twenty-four month period beginning January 01, 2001
through December 31, 2002 ("Extended Purchase Period"). The parties shall
continue to perform their respective obligations under and remain subject to the
provisions of Amendment 01 until December 31, 2000, after which the provisions
of this Amendment 02 will apply to the Extended Purchase Period (January 01,
2001, through December 31, 2002).

II. Article 1 Purchase of Materials is hereby amended to include the following:

1.2 IPG shall purchase and SDL shall sell the Products for the Extended Purchase
    Period at the prices set forth in Exhibit C and pursuant to the delivery
    schedule in Exhibit A. The initial delivery schedule in Exhibit A may be
    revised by IPG in accordance with the Release Order procedure described in
    Article 4 if IPG's requirements change. However IPG acknowledges that the
    unit prices provided for the Product(s) in the Exhibit C are based on an
    agreed minimum run rate for total ordered Product. In the event IPG does not
    place Release Orders for Products to meet the minimum total quantities
    stated below for the specified time periods. IPG shall be subject to the
    following         for the units ordered in such time period. Any
    incurred         will be invoiced to IPG within any such quarter
    that such a       of Product quantities occurs:

    Period                  Minimum Qty
    ----------------------------------------------------------------------------
    Any given Quarter       Exhibit A Total
    Q1 '01 thru Q4'01       Quarterly Demand

    Any given Quarter       Exhibit A Total

/1/ This total quantity may be adjusted due to product mix allowances
for          quantities as described in Exhibit A.

                                      28
<PAGE>

        Q1 '02 thru Q4'02     Quarterly Demand

        Where ATQD=Actual Total Quarterly Demand,
              EATQD=Exhibit A Total Quarterly Demand.

        If IPG does not place orders to take delivery of at least   of the total
        quantity in any given quarter shown in Exhibit A, IPG shall be deemed in
        material breach of this Agreement in accordance with Article 13 and
        shall be subject to the           and
                 below, based upon the sum total of parts up to and including
        the quarter in question.

1.3     Subject always to SDL conforming in all material respects with its
        obligations as set out in this Agreement, then IPG undertakes to
        purchase from SDL a quantity of     /2/  of Products during the Extended
        Purchase Period. If upon expiry or termination of the Extended Purchase
        Period of this Agreement the total quantity of Product for which IPG has
        taken delivery is less than        of the total    /2/ then IPG shall in
        addition to any obligations it may have pursuant to Article 13
        "Termination" pay to SDL a sum calculated as follows:

        a)     For a requested total two-year demand up to         of the two
               year cumulative total in Exhibit A:

        b)     For a requested total two-year demand greater than        units:

        The payment of any such sum shall be in full and final settlement of any
        claim by SDL in respect of its infrastructure investment resulting from
        IPG's failure to take delivery of a quantity of          of the total
        units/2/ of Product within the Extended Purchase Period.

III.    Article 4 Release Procedure is hereby amended to include the following:

4.1 (d) IPG shall issue Release Orders for Product deliveries in the Extended
Purchase Period in accordance with a 24-month rolling horizon forecast. All time
zones shall remain as defined in this Article 4.1. For purposes of the Extended
Purchase Period, the Planning zone shall initially be months 7-24. Product
quantities forecasted for delivery in the various zones of the Extended
Purchase Period may be varied as described, subject always to the terms of
Article 1. However, in no event, shall IPG's forecasted quantity for Product in
any given quarter be increased by greater than     over that same quarter's
initial forecasted demand contained in Exhibit A. Additionally, any forecasted
demand for total Product may not be increased by greater than   over the initial
total quantity for Product in Exhibit A. In the event IPG requests such
increases, SDL reserves the right to equitably adjust the                and
        accordingly.

-------------------------------
/2/ This total quantity may be adjusted due to product mix allowances
for          quantities as described in Exhibit A.

                                      29
<PAGE>

SDL reserves the right to equitably adjust the                     and
               accordingly.

IV.     Article 13 Termination is hereby amended to include the following:

13.4    In the event of a material breach by IPG, IPG shall remain responsible
        for all penalties, liabilities and other obligations to SDL as of the
        date of termination.

13.5    In the event of a material breach of this Agreement by SDL, SDL shall be
        liable to IPG for a         of      .                      by SDL to
        IPG shall constitute full and final settlement between the parties for
        such material breach by SDL.

13.6    In the event IPG cancels a Release Order at any time prior to delivery
        and SDL is not in material breach of this Agreement, IPG shall be liable
        for:

V.      Article 16 Confidential Information is hereby amended to include the
        following:

16.6    IPG and SDL agree that this Agreement is considered Confidential
        Information and subject to the provisions of this Article 16. Neither
        party shall without the prior written consent of the other party,
        publicize the fact or contents of this Agreement, except as the company
        is required to be disclosed under applicable law, or as the company
        discloses to it's accountants, lawyers, commercial and investment
        bankers or other advisors, notwithstanding anything herein to the
        contrary. In the event that SDL or IPG is required to release
        information related to this Agreement (other than to the party's
        accountants, lawyers, commercial and investment bankers or other
        advisors), timely consent notice to the other party shall be provided by
        IPG for prior to such release of information to the extent possible.

VI.     Article 19 Term is hereby amended to include the following:

19.1    The term of this Agreement is hereby extended for an additional twenty-
        four (24) month period for a total of forty-five (45) months from the
        Commencement Date.

                                      30
<PAGE>

VII. Exhibits. A - Delivery Schedule, B - Product Specification, and C - Product
Pricing, are modified as set forth in this Amendment 02 and attached hereto.

VIII. The above specified modifications constitute a formal Amendment to the
Agreement.  Except as herein modified, all other specifications, terms and
conditions currently applicable to the Agreement remain unchanged.

IN WITNESS WHEREOF, the parties hereto have executed this Amendment 02 by their
respective duly authorized representatives as of the last date set forth below:

Signed for and on behalf of IPG Corporation,

Authorized Signatory: /s/ Valentin Gaponstev, Ph.D.               Date: 11/14/00
                      -----------------------------------------         --------
Name:                 Valentin Gaponstev, Ph.D./John Dalton
Title:                CEO/President, IPG Corporation

Signed for and on behalf of SDL, Inc.

Authorized Signatory: /s/ Gordon Mitchard, Ph.D.                  Date: 11/15/00
                      -----------------------------------------         --------
Name:                 Gordon Mitchard, Ph.D.
Title:                General Manager
                      Industrial Laser Group, SDLI

                                      31
<PAGE>

                                   Exhibit A

Exhibit A is hereby amended to include the following initial delivery schedule
for the Extended Purchase Period:

                                      32
<PAGE>

Exhibit B: PRODUCT SPECIFICATION

                                      33
<PAGE>

Exhibit B: PRODUCT SPECIFICATION

                                      34
<PAGE>

                                      35
<PAGE>

                          Exhibit B - Specifications
                          --------------------------

Device Characteristics*            Symbol       Min.    Typ.    Max.    Units
-----------------------------------------------------------------------------
        Power
        Peak Wavelength
        Spectral Width
        Slope Efficiency
        Conversion Efficiency
        Emitting Dimension
        Beam Divergence
                Parallel
                Perpendicular
        Threshold Current
        Operating Current
        Operating Voltage
        Series Resistance
        Thermal Resistance
        Recommended Case Temp.

Absolute Maximum Ratings
        Reverse Voltage
        Case Operating Temp.
        Storage Temp. Range
        Lead Soldering Temp.

Accepted By: /s/ Ben Li
            -----------

Date:   Nov. 13, 2000

                                      36
<PAGE>

                                                             80 Rose Orchard Way
                                                              San Jose, CA 95134
                                                                 408-943-4505(P)
                                                                 408-943-4260(F)

Exhibit B: Product Specification

Device Performance Rating:
-------------------------
No other device rating performance testing is included or implied.

Note: All specifications to be reviewed subsequent to completion of evaluation
----
order and prior to placement of high volume qty. order.

Accepted By: /s/ Ben Li
             ----------------------
Date: Nov. 13, 2000
      -----------------------------

                                      37
<PAGE>

Exhibit B: PRODUCT SPECIFICATION

                                  Accepted By Ben Li
                                    Date Nov. 13, 2000

                                      38
<PAGE>

Exhibit B: PRODUCT SPECIFICATION

                                                          Accepted By /s/ Ben Li
                                                                      ----------

                                                              Date Nov. 13, 2000
                                                                   -------------

                                      39
<PAGE>

                                   Exhibit C

Exhibit C is hereby amended to include the following pricing for the Extended
Purchase Period:

                                      40<PAGE>

                                                                   EXHIBIT 10.19

                            STOCK ISSUANCE AGREEMENT
                         FOR AWARDS OF RESTRICTED STOCK

                                Pursuant to the
                                 IPG PHOTONICS
                        2000 INCENTIVE COMPENSATION PLAN

     THIS STOCK ISSUANCE AGREEMENT ("Agreement") is made effective as of the
22nd day of January, 2001, and is entered into by and between IPG Photonics
Corporation, (hereinafter called the "Company") and Vincent Au-Yeung
(hereinafter called the "Awardee").

     WHEREAS, the Awardee has become employed by the Company, an Affiliate or
Group Company in an important capacity, commencing January 22, 2001 as set forth
in Awardee's Employment Agreement dated November 29, 2000 ("Employment
Agreement");

     WHEREAS, the Company desires to provide an incentive to the Awardee so that
he will exert his utmost efforts on the Company's behalf and thus enhance its
chances of success;

     WHEREAS, the Company believes that this may be accomplished by encouraging
the Awardee to acquire a proprietary or an increased proprietary interest in the
Company; and

     WHEREAS, in furtherance thereof, the Company wishes to grant certain of its
shares of voting common stock ("Shares") to the Awardee under the IPG Photonics
2000 Incentive Compensation Plan (the "Plan") subject, however, to certain
restrictions under the Plan, and consistent with the terms and conditions of
Awardee's Employment Agreement.

     NOW, THEREFORE, in consideration of the premises and of the mutual
covenants and agreements hereinafter set forth, the parties hereto mutually
covenant and agree as follows:

1.   Definitions.  All terms used herein that are not otherwise defined shall
     -----------
     have the meanings ascribed to them in the Plan, unless otherwise expressly
     provided herein as being defined in the Employment Agreement.

2.   Grant of Stock Subject to Restrictions.  The Awardee hereby acknowledges
     --------------------------------------
     that the Company has on this date granted to the Awardee 500,000 Shares.
     The Company and Awardee acknowledge that such Shares have been granted
     pursuant to the restrictions contained herein and shall hereinafter
     sometimes be referred to as the "Restricted Stock."

3.   Purchase Price; Other Deliveries.  The aggregate purchase price for the
     --------------------------------
     Restricted Stock shall be Five Hundred Thousand Dollars ($500,000), and
     shall be paid by certified check or wire transfer.  Awardee shall also
     deliver a duly-executed blank Assignment Separate from Certificate (in the
     form attached hereto as Exhibit A) with respect to the Restricted Stock.
     The Company shall deliver to Awardee a certificate representing 250,000 of
     such shares
<PAGE>

     of Restricted Stock, and a separate certificate representing 250,000 of
     such shares of Restricted Stock shall be held by the Company, subject to
     the terms and conditions of the Pledge Agreement, dated of even date
     herewith. Awardee hereby agrees that if he shall sell any shares of
     Restricted Stock, that he shall use the proceeds of such sale to repay the
     Promissory Note of Awardee to the Company dated of even date herewith,
     regardless of whether such shares are subject to the Pledge Agreement.

4.   Restrictions; Risk of Forfeiture.  Awardee hereby agrees that until such
     --------------------------------
     restrictions lapse as herein provided, he will not sell, assign, transfer,
     pledge or encumber or otherwise dispose of any of the Restricted Stock,
     except as provided herein, without the prior written consent of the Company
     as authorized by the Committee.  If and only if the Awardee's employment is
     terminated by the Company for Cause, or Awardee terminates his employment
     for any reason other than Good Reason, both terms being defined in the
     Employment Agreement, in either case on or before July 19, 2001, the
     Restricted Stock shall be immediately subject to a right of repurchase by
     the Company for the purchase price set forth in Section 3, and the Company
     shall have the right to defer payment pursuant to the terms and conditions
     set forth in the Plan and Section 10 herein.

5.   Lapse of Restrictions.  The risk of forfeiture set forth in Section 4 shall
     ---------------------
     lapse effective July 20, 2001, subject to the further restrictions set
     forth in Section 7.

6.   Incorporation by Reference.  The terms and conditions of the Plan, as it
     --------------------------
     now exists and as it may be amended from time to time, are hereby
     incorporated by reference into this Agreement.  The Restricted Stock is
     granted herein pursuant to and subject to the Plan.  In the event of any
     conflict between the terms of this Agreement and the terms of the Plan, the
     terms of the Plan shall control, except as expressly provided in Section 4
     above and Section 8 below.

7.   Further Transfer Restrictions.
     -----------------------------

     a.   Restriction on Transfer. Subject to the other provisions of this
          -----------------------
          Agreement for the first 6 months following the date of grant of the
          Restricted Stock, but in no event prior to July 20, 2001, Awardee may
          not sell, exchange, or transfer the Restricted Stock to anyone,
          without the prior written consent of the Company, which consent may be
          withheld in its sole and absolute discretion, except for Permitted
          Transfers (as defined below).

     b.   Transferee Obligations.  Each person (other than the Company) to whom
          ----------------------
          the Restricted Stock is transferred by means of a transfer expressly
          permitted under this Agreement must, as a condition precedent to the
          validity of such transfer, acknowledge in writing to the Company that
          such person is bound by the provisions of this Agreement and that the
          transferred Shares are subject to (i) the Call Right (as defined
          below), (ii) the First Refusal Right (as defined below) and (iii) the
          Lock-Up (as defined below), to the same extent such Shares would be so
          subject if retained by Awardee.

     c.  Lock-Up.
         -------

                                      -2-
<PAGE>

          (i)  In connection with any underwritten public offering by the
               Company of its equity securities pursuant to an effective
               registration statement filed under the Securities Act, including
               the Company's initial public offering, Awardee shall not sell,
               make any short sale of, loan, hypothecate, pledge, grant any
               option for the purchase of, or otherwise dispose or transfer for
               value or otherwise agree to engage in any of the foregoing
               transactions with respect to any Restricted Stock without the
               prior written consent of the Company or its underwriters.  Such
               restriction (the "Lock-Up") shall be in effect for a period of up
               to 180 days from and after the effective date of the final
               prospectus for the offering or otherwise as may be required by
               such underwriters.  Such Lock-Up may be subject to such other
               restrictions, conditions and limitations as the underwriters
               impose.

          (ii) Awardee shall be subject to the Lock-Up only if and to the extent
               that the officers and directors of the Company are also subject
               to similar restrictions, including restrictions on Permitted
               Transfers (as defined below).

8.  Call Right.
    ----------

     a.   Grant.  If the Awardee's employment is terminated by the Company for
          -----
          Cause as defined in the Employment Agreement, effective on such date
          and prior to the completion of an IPO, the Company shall have the
          right to purchase, and the Awardee shall have the corresponding
          obligation to sell, upon delivery of written notice to Awardee, all
          and not less than all of the Shares then owned by Awardee, ownership
          of which Shares was acquired hereunder (such repurchase rights of the
          Company, being referred to hereinafter as the "Call Rights").  The
          purchase price of the Shares subject to the Company's Call Rights
          shall be the Fair Market Value of such Shares as of the date the
          Company mails or otherwise delivers such written notice to the
          Awardee, provided, however, the purchase price shall be the price set
                   --------  -------
          forth in Section 3 of the Agreement for terminations occurring during
          the period and for the reasons set forth in Section 4 herein.

          b.   The Company shall have the right to defer payment of the purchase
               price under Section 8.a pursuant to the terms and conditions set
               forth in the Plan and Section 10 herein.

9.  Right of First Refusal.
    ----------------------

     a.   Grant.  Prior to an IPO, the Company shall have a right of first
          -----
          refusal (the "First Refusal Right"), exercisable in connection with
          any proposed transfer of the Shares, except with respect to any
          Permitted Transfer (as defined below).

     b.   Notice of Intended Disposition.  In the event Awardee desires to
          ------------------------------
          accept a bona fide third-party offer for the transfer of any or all of
          the Restricted Stock (the Restricted Stock subject to such offer to be
          hereinafter referred to as the "Target Shares"), Awardee shall
          promptly (i) deliver to the Company written notice (the

                                      -3-
<PAGE>

          "Disposition Notice") of the terms of the offer, including the
          purchase price and the identity of the third-party offeror, and (ii)
          provide satisfactory proof that the disposition of the Target Shares
          to such third-party offeror would not be in contravention of the
          provisions set forth in Sections 4, 7 and 11.

     c.   Exercise of the First Refusal Right.  The Company shall, for a period
          -----------------------------------
          of ten (10) days following receipt of the Disposition Notice, have the
          right to repurchase all and not less than all of the Target Shares
          subject to the Disposition Notice upon the same terms as those
          specified therein or upon such other terms (not materially different
          from those specified in the Disposition Notice) to which Awardee
          consents.  Such right shall be exercised by delivery of written notice
          (the "Exercise Notice") to Awardee prior to the ten (10) day exercise
          period.  The Company shall effect the repurchase of such shares,
          including payment of the purchase price, not more than five (5)
          business days after delivery of the Exercise Notice; and at such time
          the certificates representing the Target Shares shall be delivered to
          the Company.

          Should the purchase price specified in the Disposition Notice be
          payable in property other than cash or evidences of indebtedness, the
          Company shall have the right to pay the purchase price in the form of
          cash equal in amount to the value of such property.  If Awardee and
          the Company cannot agree on such cash value within ten (10) days after
          the Company's receipt of the Disposition Notice, the valuation shall
          be made by an appraiser of recognized standing selected by Awardee and
          the Company or, if they cannot agree on an appraiser within twenty
          (20) days after the Company's receipt of the Disposition Notice, each
          shall select an appraiser of recognized standing and the two (2)
          appraisers shall designate a third appraiser of recognized standing,
          whose appraisal shall be determinative of such value.  The cost of
          such appraisal shall be shared equally by Awardee and the Company.
          The closing shall then be held on the later of (i) the fifth (5th)
                                                -----
          business day following delivery of the Exercise Notice or (ii) the
          fifth (5th) business day after such valuation shall have been made.

     d.   Non-Exercise of the First Refusal Right.  In the event the Exercise
          ---------------------------------------
          Notice is not given to Awardee prior to the expiration of the ten (10)
          day exercise period, Awardee shall have a period of ninety (90) days
          thereafter in which to sell or otherwise dispose of the Target Shares
          to the third-party offeror identified in the Disposition Notice upon
          terms (including the purchase price) no more favorable to such third-
          party offeror than those specified in the Disposition Notice;
          provided, however, that any such sale or disposition must not be
          --------  -------
          effected in contravention of the provisions of Sections 4, 7 and 11.
          The third-party offeror shall acquire the Target Shares subject to the
          provisions of this Agreement as set forth in 7.b.  In the event
          Awardee does not effect such sale or disposition of the Target Shares
          within the specified (90)-day period, the First Refusal Right shall
          continue to be applicable to any subsequent disposition of the Target
          Shares by Awardee until such right lapses.

                                      -4-
<PAGE>

     e.   Recapitalization/Reorganization.
          -------------------------------

          (i)  Any new, substituted or additional securities or other property
               which is by reason of any Recapitalization distributed with
               respect to the Restricted Stock shall be immediately subject to
               the First Refusal Right, but only to the extent the Restricted
               Stock is at the time covered by such right.

          (ii) In the event of a Reorganization, the First Refusal Right shall
               remain in full force and effect and shall apply to the new
               capital stock or other property received in exchange for the
               Restricted Stock in consummation of the Reorganization, but only
               to the extent the Restricted Stock are at the time covered by
               such right.

     f.   Lapse.  The First Refusal Right shall lapse on the date the Shares
          -----
          become readily tradable on an established securities market.  However,
          the Lock-Up shall continue to remain in full force and effect
          following the lapse of the First Refusal Right.

     g.   Permitted Transfer.  For the purpose of Section 9(a), the term
          ------------------
          "Permitted Transfer" shall mean, with respect to the Shares, any sale,
          conveyance, exchange, assignment, pledge, encumbrance, gift, bequest,
          hypothecation or other transfer or disposition by any other means,
          whether for value or no value and whether voluntary or involuntary
          (including, without limitation, by merger or operation of law), or any
          agreement to do any of the foregoing, by Awardee to his Immediate
          Family.  The term "Immediate Family" means, and is limited to,
          Awardee's current spouse, parents, parents-in-law, grandparents,
          children, siblings (and their lineal descendents), grandchildren, and
          Awardee's beneficiaries and heirs.  A trust, estate, family
          partnership, limited liability company or corporation entitled to
          federal income tax treatment pursuant to subchapter S of the Internal
          Revenue Code, all of the beneficiaries, partners, members or
          shareholders of which consist of Awardee or members of his Immediate
          Family, shall be considered his Immediate Family for the purposes of
          this Agreement.

10.  Right to Defer Payment.  At the discretion of the Committee, payments to
     ----------------------
     Awardee may be made by the Company in the form of a single lump sum or
     installments, provided in the case of installment payments the Company has
     represented in writing to Awardee that its corporate cash flow needs do not
     permit a lump sum payment, as determined in good faith by the Board of
     Directors of the Company.  Installment payments shall be made in full no
     later than six (6) months from the date of disposition and will, be
     credited monthly with interest using an interest rate equal to the annual
     rate of interest on 30-year Treasury securities as of the beginning of each
     such monthly crediting period (as determined by the Committee).

                                      -5-
<PAGE>

11.  Restrictive Legend; Restrictions on Disposition; Securities Matters.
     -------------------------------------------------------------------

     (a)  Awardee hereby agrees that the certificates for the Restricted Stock
          shall be inscribed with the following legend:

               "The shares of stock evidenced by this certificate are subject to
               the terms and restrictions of the IPG Photonics 2000 Incentive
               Compensation Plan and the terms of the Stock Issuance Agreement
               ("Agreement") between the Company and Vincent Au-Yeung dated as
               of January 22, 2001.  Such shares are subject to repurchase and
               cancellation under the terms of such Plan and Agreement, and such
               shares shall not be sold, transferred, assigned, pledged,
               encumbered or otherwise alienated or hypothecated except pursuant
               to the provisions of such Plan and Agreement.  A copy of the Plan
               is available from the Company upon request."

          In addition, if shares are awarded prior to a completed public
          offering, the certificates shall also be inscribed with the following:

               "The shares of stock evidenced by this certificate have not been
               registered under the Securities Act of 1933 (the "Securities
               Act") or the securities laws of any state.  These shares may not
               be sold or transferred unless the transaction is registered under
               the Securities Act and applicable state law or exempt from
               registration thereunder."

     (b)  Awardee shall make no disposition of the Restricted Stock unless and
          until there is compliance with all of the following requirements:

          (i)   Awardee shall have provided the Company with written summary of
                the terms and conditions of the proposed disposition.

          (ii)  Awardee shall have complied with all requirements of this
                Agreement applicable to the disposition of the Restricted Stock.

          (iii) Awardee shall have provided the Company with written assurances,
                including an opinion of counsel, in form and substance
                satisfactory to the Company, that (a) the proposed disposition
                does not require registration of the Restricted Stock under the
                Securities Act or applicable state securities laws, or (b) all
                appropriate action necessary for compliance with the
                registration requirements of the Securities Act and applicable
                state securities laws or any exemption from registration
                available under the Securities Act (including Rule 144) and
                applicable state securities laws has been taken.

                                      -6-
<PAGE>

     (c)  The Company shall not be required (i) to transfer on its books
          Restricted Stock which has been sold or transferred in violation of
          the provisions of this Agreement or (ii) to treat as the Awardee,
          owner or holder of the Restricted Stock, or otherwise to accord
          voting, dividend or liquidation rights to, any transferee to whom the
          Restricted Stock has been transferred in contravention of this
          Agreement.

     (d)  The Restricted Stock has not been registered under the Securities Act
          and is being issued to Awardee in reliance upon the exemption from
          such registration provided by SEC Rule 701 for stock issuances under
          compensatory benefit plans such as the Plan.  Awardee hereby confirms
          that Awardee has been informed that the Restricted Stock constitutes
          restricted securities under the Securities Act and may not be resold
          or transferred unless the Restricted Stock is first registered under
          the Federal securities laws and applicable state securities laws or
          unless an exemption from such registration is available.  Accordingly,
          Awardee hereby acknowledges and agrees that Awardee is prepared to
          hold the Restricted Stock for an indefinite period and that Awardee is
          aware that SEC Rule 144 issued under the Securities Act which exempts
          certain resales of securities is not presently available to exempt the
          resale of the Restricted Stock from the registration requirements of
          the Securities Act.

     (e)  Awardee hereby represents and warrants to the Company that Awardee is
          acquiring the Restricted Stock for Awardee's own account, for
          investment purposes, and not with a view to, or for resale in
          connection with, the distribution  of such Restricted Stock.

12. Additional Restricted Stock.  Awardee agrees that the term "Restricted
    ---------------------------
    Stock" shall include any shares or other securities which he may receive or
    be entitled to receive as a result of the ownership of the original
    Restricted Stock whether the same are issued as a result of a
    Recapitalization or Reorganization.

13. Severability.  In the event that any one or more of the provisions or
    ------------
    portion thereof contained in this Agreement shall for any reason be held to
    be invalid, illegal, or unenforceable in any respect, the same shall not
    invalidate or otherwise affect any other provisions of this Agreement and
    this Agreement shall be construed as if the invalid, illegal, or
    unenforceable provision or portion thereof had never been contained herein.

14. Entire Agreement.  Except as set forth in the  Employment Agreement, this
    ----------------
    Agreement constitutes and contains the entire Agreement and understanding
    between the parties with respect to the subject matter hereof and supersedes
    any and all prior agreements, if any, understandings and negotiations
    relating thereto.  No promise, understanding, representation, inducement,
    condition or warranty not set forth herein has been made or relied upon by
    any party hereto.

15. Notice.   Any notice which either party hereto may be required or permitted
    -------
    to give to the other shall be in writing, and may be delivered personally or
    by mail, postage prepaid, if to the Company, addressed to the Company at the
    following address:

                                      -7-
<PAGE>

                                 IPG Photonics Corporation
                                 P.O. Box 519
                                 660 Main Street
                                 Sturbridge, MA    01566
                                 Attention:  Angelo Lopresti, Esq.

   or at any other address as the Company, by notice to the Awardee, may
   designate in writing from time to time; and, if to the Awardee, addressed to
   the Awardee at the Awardee's address as set forth next to the Awardee's
   signature below, or at any other address as the Awardee by notice to the
   Company, may designate in writing from time to time.

16. Binding Effect.  Subject to the other terms hereof, this Agreement shall be
    --------------
    binding upon and inure to the benefit of the heirs, beneficiaries, legal
    representatives and successors of the parties.

17. Governing Law.  This Agreement shall be construed by, enforced in accordance
    -------------
    with and governed by the substantive laws of the State of Delaware without
    giving effect to the conflicts of laws provisions thereof.

18. Waiver.  No waiver by either party of the application of any term, provision
    ------
    or condition of this Agreement, or a breach thereof by the other party,
    shall constitute a waiver of any succeeding breach of the same or any other
    provision hereof.  No such waiver shall be valid unless executed in writing
    by the party making the waiver.

19. Transferability.  The Awardee shall not transfer, sell, pledge, assign or
    ---------------
    otherwise dispose of or encumber the Shares awarded hereunder other than as
    set forth in this Agreement and the Plan.  Any attempted transfer, sale,
    pledge, assignment or other disposition or encumbrance of such Shares, or of
    Awardee's rights and obligations under this Agreement, contrary to the
    provisions of this Agreement shall be null and void.

20. Cancellation of Shares.  If the Company shall make available, at the time
    ----------------------
    and place and in the amount and form provided in this Agreement, the
    consideration for the Restricted Stock to be repurchased in accordance with
    the provisions of this Agreement, then from and after such time, the person
    from whom such shares are to be repurchased shall no longer have any rights
    as a holder of such shares (other than the right to receive payment of such
    consideration in accordance with this Agreement).  Such shares shall be
    deemed purchased in accordance with the applicable provisions hereof, and
    the Company shall be deemed the Awardee and holder of such shares, whether
    or not the certificates therefor have been delivered as required by this
    Agreement.

21. Awardee Undertaking.  Awardee hereby agrees to take whatever additional
    -------------------
    action and execute whatever additional documents the Company may deem
    necessary or advisable in order to carry out or effect one or more of the
    obligations or restrictions imposed on either Awardee or the Restricted
    Stock pursuant to the this Agreement.

                                      -8-
<PAGE>

22. Counterparts.  This Agreement may be executed in one or more counterparts,
    ------------
    each of which shall be deemed to be an original, but all of which together
    shall constitute one and the same instrument.

    IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of
    the day and date first set forth above.

                              IPG PHOTONICS CORPORATION

                              By: /s/ Dr. Valentin P. Gapontsev
                                  -------------------------------------------

                              Title: Dr. Valentin P. Gapontsev
                                     ----------------------------------------

                              AWARDEE

                              By: /s/ Vincent Au-Yeung
                                  -------------------------------------------

                              Name: Vincent Au-Yeung
                                    -----------------------------------------

                              Address:
                                       --------------------------------------

                                      -9-
<PAGE>

                             SPOUSAL ACKNOWLEDGMENT

     The undersigned spouse of Awardee has read and hereby approves the
foregoing Stock Issuance Agreement.  In consideration of the Company's granting
Awardee the right to acquire the Restricted Stock in accordance with the terms
of such Agreement, the undersigned hereby agrees to be irrevocably bound by all
the terms of such Agreement.

                              AWARDEE'S SPOUSE

                              By:
                                  ---------------------------------------

                              Name:
                                    -------------------------------------

                              Address:
                                       ----------------------------------

                                      -10-
<PAGE>

                                   EXHIBIT A

                      ASSIGNMENT SEPARATE FROM CERTIFICATE

     FOR VALUE RECEIVED ________________ hereby sell(s), assign(s) and
transfer(s) to IPG Photonics Corporation (the "Company"), ____________ (______)
shares of the voting common stock, par value $0.0001 per share, of the Company
standing in his or her name on the books of the Company represented by
Certificate No._______ herewith and do(es) hereby irrevocably constitute and
appoint _______________ Attorney to transfer such stock on the books of the
Company with full power of substitution in the premises.

Dated: _________________________

                              Signature   ___________________________________
                                          Vincent Au-Yeung

Instruction:  Please do not fill in any blanks other than the signature line.
Please sign exactly as you would like your name to appear on the issued stock
certificate.  The purpose of this assignment is to enable the Company to
exercise the Call Rights without requiring additional signatures on the part of
Awardee.

                                      -11-

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