Document:

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                                                                   Exhibit 10.20

     THIS SERVICES AGREEMENT (this "Agreement"), is made as of January 1, 2001,
by and between IPG Photonics (UK) Ltd., a company organized under the laws of
the United Kingdom ("IPG"), and IP Fibre Devices Ltd., a company organized under
the laws of the United Kingdom ("Fibre Devices").

                                  WITNESSETH:
                                  ----------

     WHEREAS, Fibre Devices rents certain parcels of real estate and employs
certain personnel; and

     WHEREAS, IPG plans to commence operations in the United Kingdom and would
like to share an allocated portion of certain real estate and other costs of
Fibre Devices and offer employment to certain employees of Fibre Devices.

     NOW, THEREFORE, in consideration of the premises and the mutual covenants
contained herein, the parties, intending to be legally bound, hereby agree as
follows:

                                   ARTICLE I
                                 COST SHARING

1.1  Costs.
     -----

     a.  Fibre Devices shall provide use of its offices, including electricity,
heating, furniture and office equipment (collectively, "Office Expenses"), to
IPG.

     b.  IPG shall pay directly for its telecommunications charges.

     c.  For the year beginning January 1, 2001, IPG shall pay the amount of
$[250,000] for its portion of Office Expenses.  In subsequent years, the amount
that IPG will pay shall be agreed to by the parties and shall reflect actual
directly related costs of such Office Expenses used by IPG.

1.2  Employment.  IPG agrees to offer employment to Dr. Sergei Popov and Alice
Ordabaeva substantially the same as their terms of employment by Fibre Devices,
provided that such terms are reasonably acceptable to IPG.

1.3  Salary.  During the first year of the term of this Agreement, IPG agrees to
     ------
pay 75% of the current salary of Caesar Vishowaty for as long as he is employed
by Fibre Devices.  Mr. Vishowaty shall dedicate not less than 75% of his
business time and attention to IPG.  After the first year, the parties hereto
shall agree on the appropriate allocation for the following year.

1.4  Term.  The term of this Agreement shall be two years, commencing on the
     ----
date of this Agreement.  Provided that neither party has given written notice of
termination to the other at least ninety days prior to the expiration of the
term of this Agreement, or any renewal term, this
<PAGE>

Agreement shall be deemed to be renewed for successive one year terms at the
expiration of the original or any renewal term.

                                  ARTICLE II
                                INDEMNIFICATION

Each party (the "Indemnifying Party") shall defend, indemnify and hold harmless
the other party, including its directors, officers and employees (collectively,
the "Indemnified Party"), from and against any and all demands, claims, actions
or causes of action, losses, damages, liabilities, costs and expenses,
including, without limitation, judgments, interest, penalties, settlement
amounts, court costs and reasonable attorneys' fees and expenses, asserted
against, imposed upon or incurred by the Indemnified Party arising out of or
relating to any actual or alleged act or omission of the Indemnifying Party
related to its performance of its obligations hereunder.  The foregoing
indemnification obligation shall survive the expiration or earlier termination
of this Agreement.

                                  ARTICLE III
                                 MISCELLANEOUS

3.1  Assignment.  This Agreement shall not be assigned by IPG without the prior
     ----------
written consent of Fibre Devices.  Any attempted assignment or transfer of any
rights, or attempted delegation of any duties or obligations, under this
Agreement by IPG without such prior written consent shall be void and of no
effect.  Fibre Devices reserves the right to assign any rights and delegate any
duties or obligations hereunder to another affiliate of Fibre Devices upon
written notice to IPG.

3.2  Notices.  Any notice required or permitted by this Agreement to be given
     -------
shall be in writing and shall be addressed to either party at its principal
place of business, or at such other address as it may notify to the other party.
Each such notice shall be sent by registered or certified mail or delivered by
hand, or by facsimile or a private delivery service and shall be deemed to have
been given on the date of its receipt at the address to which such notice is so
directed, regardless of any other date that may appear thereon.

3.3  Waiver.  The failure of either party to insist upon a strict performance of
     ------
any of the terms or provisions of this Agreement or to exercise any option,
right or remedy herein contained, shall not be construed as a waiver or as a
relinquishment for the future of such term, provision, option, right or remedy,
but the same shall continue and remain in full force and effect throughout the
term of this Agreement.  No waiver by either party of any term or provision
hereof shall be deemed to have been made unless expressed in writing and signed
by an authorized representative of such party.

3.4  Severability.  In the event that any one or more of the provisions
     ------------
contained in this Agreement shall for any reason be held to be invalid, illegal
or unenforceable in any respect, such invalidity, illegality or unenforceability
shall not affect any other provision hereof and this Agreement shall be
construed as if such invalid, illegal or unenforceable provision had never
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been contained herein and, in lieu of each such illegal, invalid or
unenforceable provision, there shall be added as a part of this Agreement, a
provision as similar in terms to such illegal, invalid or unenforceable
provision as may be possible and be legal, valid and enforceable.

3.5  Entire Agreement; Amendment.  This Agreement, together with all other
     ---------------------------
writings signed by the parties expressly stated to be supplementary hereto and
together with any instruments to be executed and delivered pursuant hereto
constitutes the entire agreement between the parties, and supersedes all prior
understandings and writings concerning the subject matter hereof.  This
Agreement may be amended only by a writing signed by authorized representatives
of both parties.

3.6  Further Assurances.  Each of the parties shall from time to time, at the
     ------------------
request of the other party, execute and deliver such other agreements and
instruments and take such other action as may reasonably be requested in order
to more effectively consummate the transactions contemplated hereby.

3.7  Successors and Assigns.  All of the terms and provisions of this Agreement
     ----------------------
shall be binding upon and shall inure to the benefit of the parties hereto and
their respective successors and permitted assigns becoming such in accordance
with the terms of this Agreement.  Nothing contained in this Agreement shall be
deemed to create any third party beneficiary or other rights hereunder in favor
of any person, firm, corporation or other entity not a party to this Agreement.

3.8  Governing Law.  This Agreement, and the rights and obligations of the
     -------------
parties hereto, shall be governed by and construed in accordance with the laws
of the United Kingdom without reference to its conflict of laws rules.

3.9  Headings.  The headings of the articles and sections herein are for
     --------
convenience only and shall not affect the construction hereof.

3.10  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.
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     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed in their respective corporate names by their duly authorized
officers as of the date first written above.

                                IPG PHOTONICS (UK) LTD.

                                By: /s/ Angelo P. Lopresti
                                   --------------------------------------
                                   Name:  Angelo P. Lopresti
                                   Title: Secretary

                                IP FIBRE DEVICES LTD.

                                By: /s/ Timothy P.V. Mammen
                                   --------------------------------------
                                Name:  Timothy P.V. Mammen
                                Title: General Manager and Secretary<PAGE>

                                                                   Exhibit 10.22

                             STANDSTILL AGREEMENT

     THIS STANDSTILL AGREEMENT  (this "Agreement") is entered into this 21st day
of December, 2000, by and among Pediatric Services of America, Inc., a Delaware
corporation (the "Company"), The D3 Family Fund, L.P., a Washington limited
partnership (the "D3 Fund"), David Nierenberg, and Haredale, Ltd., a Bahamas
corporation (collectively, with the D3 Fund, and David Nierenberg,
"Purchasers").

     WHEREAS, Purchasers are the beneficial owners of 14.9% of the outstanding
common stock of the Company as of December 20, 2000;

     WHEREAS, Purchasers have expressed an interest in acquiring in excess of
15% of the outstanding common stock of the Company;

     WHEREAS, under the Rights Agreement dated as of September 22, 1998 between
the Company and Chasemellon Shareholder Services, L.P., n/k/a Mellon Investor
Services LLC [sic], (the "Rights Plan"), as amended December 21, 2000 (the
"First Amendment"), such ownership would cause Purchasers to be deemed an
Acquiring Person as defined in the Rights Plan; and

     WHEREAS, the Company and Purchasers agreed to enter into this Agreement as
a condition to the Board of Directors of the Company deeming Purchasers a
Special Acquiring Person, as defined in the First Amendment, in the event that
Purchasers, together with their Affiliates and Associates, as hereinafter
defined, acquire 15% or more, but less than 20%, of the outstanding Common Stock
of the Company in one or more transactions;

     NOW, THEREFORE, for and in consideration of the premises, the mutual
covenants and agreements contained herein, and other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties hereby agree as follows:

     1.  Standstill Agreement. For a period of two (2) years from the date of
this Agreement, the Purchasers, together with their Affiliates and Associates
shall not, directly or indirectly, alone or in concert with others:

         (a) acquire, offer to acquire or agree to acquire, or announce an
intention to acquire or offer to acquire, whether by purchase, tender or
exchange offer, through the acquisition of control of another person, by joining
a partnership, limited partnership, syndicate or other "group" as defined in
Section 13(d)(3) of the Securities Exchange Act of 1934, as amended and in
effect on the date of this Agreement (the "Exchange Act"), and Rule 13d-5
promulgated thereunder or otherwise, or obtain a right to acquire (whether such
right is exercisable immediately or only after the passage of time) pursuant to
any agreement, arrangement or understanding (whether or not in writing) or upon
the exercise of conversion rights, exchange rights, rights, warrants or options,
or obtain the right to vote or dispose of or have "Beneficial Ownership" of (as
determined pursuant to Section 1(e) of the Rights Plan), including pursuant to
any agreement, arrangement or understanding, whether or not in writing, or
otherwise, any securities of the Company or any rights to acquire any securities
of the Company or any subsidiary thereof in an amount equal to or greater than
20%;

         (b) except with the approval of the Board of Directors of the Company,
seek election to, seek to place a representative on, or seek the removal of any
member of, the Board of the Directors of the Company;

         (c) except for a request made solely to the Board of Directors of the
Company, request, or announce its intention to request, the Company (or its
officers, employees or agents) to amend or waive any provision of this
Agreement.

In addition to the foregoing prohibitions, Purchasers acknowledge that they are
bound by the terms of the Rights Plan and the First Amendment.  Purchasers shall
not, however, be prohibited from consulting with the Board of Directors of the
Company with respect to business matters normally discussed between shareholders
and the management or board of directors of a publicly-traded company.

                                      20
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     2.  Company's Right of First Refusal.

         (a) For a period of two (2) years from the date of this Agreement, if
Purchasers desire to offer, sell, assign, pledge, transfer or dispose of
("Transfer") any more than 10,000 of their shares of capital stock of the
Company in any single trading day (the "Offered Shares"), Purchaser shall notify
the Company in writing of the proposed transfer (the "Notice"). The Company
shall have the right to purchase any or all of the Offered Shares at a price
equal to the average closing price of the last five (5) trading days as quoted
on the OTC Bulletin Board (or other regulated quotation service, trading market
or national securities exchange upon which the Company's securities are listed)
on the date of the Notice.

         (b) In lieu of or in addition to exercising its right to purchase any
or all of the Offered Shares, the Company shall have the right to direct the
opportunity to purchase any or all of the Offered Shares to one or more
purchasers of the Company's choosing (the "Additional Purchasers") at the price
set forth in Section 2(a) above.

         (c) If the Company and/or the Additional Purchasers, or any one or more
thereof, elects to purchase any or all of the Offered Shares, the Company and/or
the Additional Purchasers, as appropriate, shall give notice of acceptance to
the Purchaser within five (5) working days of the Notice, designating who will
purchase the Offered Shares, the number of Offered Shares to be purchased by
each, and a place, date and time for the closing of the sale and purchase of the
Offered Shares, which closing shall occur not more than five (5) working days
after the date the notice of acceptance from the Company and/or the Additional
Purchasers is duly given.

         (d) In the event the Company and/or the Additional Purchasers elect not
to exercise their right of first refusal to purchase any or all of the Offered
Shares, Purchasers shall have the right to sell the Offered Shares pursuant to
this Section 2(d). Subject to compliance with all applicable legal restrictions
on such sales, Purchasers may sell in any one day up to an amount of shares
equal to twice the average daily reported volume of trading in the Company's
securities as reported through the automated quotation system of a registered
securities association during the two calendar weeks preceding the date of sale;
provided, however, under this subsection, Purchasers may, in the context of a
negotiated block sale to an arm's length buyer, dispose of the Offered Shares in
a block sale or sales at a price within 10% of the price determined in
accordance with Section 2(a) of this Agreement.

     3.  Definitions. The following terms will have the following meanings for
purposes of this Agreement:

         (a) "Affiliate" shall have the meaning ascribed to such term in Rule
12b-2 of the General Rules and Regulations under the Exchange Act.

         (b) "Associate" shall mean:

             (i)    any corporation or organization, or parent or subsidiary of
such corporation or organization, of which a Person is an officer, director or
partner or is, directly or indirectly, the Beneficial Owner of 10 percent or
more of any class of equity securities;

             (ii)   any trust or other estate in which a Person has a beneficial
interest of 10 percent or more or as to which such Person serves as trustee or
in a similar fiduciary capacity; and

             (iii)  any parent, brother or sister (whether by whole of half
blood), ancestor, lineal descendant or spouse of David Nierenberg, or any such
relative of such spouse, who receive common shares of the Company through the
estate of David Nierenberg or through the distribution by any Purchaser of
common shares of the Company whose ownership is attributable to David
Nierenberg.

         (c) All capitalized terms used and not otherwise defined herein shall
have the meanings ascribed to them in the Exchange Act.

     4.  Notice. Any notices, requests, instructions or other documents required
to be given hereunder shall be in writing, effective when delivered personally
or by overnight delivery through a nationally

                                      21
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recognized overnight delivery service, or by facsimile (with a confirmatory copy
sent by overnight courier), to each of the parties at the addresses below or at
such other address as the parties may designate in writing.

     5.  Governing Law; Submission to Jurisdiction. This Agreement shall be
governed by, and interpreted, in accordance with the laws of the State of
Delaware, U.S.A., without giving effect to any conflicts-of-law principles.

     6.  Entire Agreement; Amendment. This Agreement represents the sole
understanding of the parties with respect to the subject matter contained
herein, superseding all previous written or oral communications,
representations, understandings, arrangements or agreements. No amendment or
modification of this Agreement or waiver of the terms and conditions herein
shall be binding unless approved in writing by the Company.

     7.  Counterparts. This Agreement may be executed in counterparts, all of
which shall be considered one and the same agreement, and shall become effective
when one or more counterparts have been signed by each of the parties and
delivered to the other party.

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<PAGE>

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

WITNESS:                          Pediatric Services of America, Inc.

By: /s/ Charlotte J. Mitchell     By: /s/ Joseph D. Sansone
   --------------------------        -----------------------------------
Name: Charlotte J. Mitchell          Joseph D. Sansone
                                     Chairman of the Board, President
                                     and Chief Executive Officer
                                     Pediatric Services of America, Inc.
                                     310 Technology Parkway
                                     Norcross, Georgia 30092-2929

WITNESS:                          The D3 Family Fund, L.P.

By: /s/ Patricia Nierenberg       By: /s/ David Nierenberg
   --------------------------        ---------------------------------
Name: Patricia Nierenberg            David Nierenberg, President
                                     Nierenberg Investment Management
                                     Company, Inc.
                                     General Partner of the D3 Family Fund, L.P.
                                     19605 NE 8/th/ Street
                                     Camas, Washington 98607

WITNESS:                          Haredale, Ltd.

By:/s/ Patricia Nierenberg        By: /s/ David Nierenberg
   --------------------------        ---------------------------------
Name: Patricia Nierenberg            David Nierenberg
                                     Portfolio Manager
                                     Haredale, Ltd.
                                     P.O. Box N-4465
                                     Nassau, New Providence
                                     The Bahamas

WITNESS:                          David Nierenberg

By: /s/ Patricia Nierenberg       By: /s/ David Nierenberg
   --------------------------        --------------------------
Name: Patricia Nierenberg            David Nierenberg, Individually

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