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                                  EXHIBIT 10.1





December 7,  2001



Mr. Thomas Meyer

1257 Glenwood Ave.

San Jose, CA 95125


         Re:      SEPARATION AGREEMENT AND RELEASE

Dear Tom:

         In accordance with our discussions, this letter sets forth the
agreements we have reached regarding the termination of your employment with
Corsair Communications, Inc. ("Corsair") and of your position as an officer and
Director of Lightbridge, Inc. ("Lightbridge").

1.       RESIGNATION FROM OFFICER AND DIRECTOR POSITIONS.

         Effective January 31, 2002, you agree to resign from your positions as
President and Chief Operating Officer and Director of Lightbridge and accept the
position described in Section 2 below. From January 1, 2002 through January 31,
2002 you will devote your time to such matters as you and Ms. Pamela D.A. Reeve
shall mutually agree upon.

2.       EMPLOYMENT STATUS FEBRUARY 1, 2002 TO FEBRUARY 15, 2002.

         Effective February 1, 2002, your status as an employee of Corsair and
officer of Lightbridge will change. As of that date, and continuing until
February 15, 2002, you agree to work in the capacity of Strategic Advisor on
special projects on a full-time basis. You will report directly to Ms. Reeve and
will devote your time to transitional matters related to your reassignment and
such other matters as you and Ms. Reeve shall mutually agree upon. During this
period, you will continue to be paid your current base salary and participate in
the Company's benefit programs on the same basis as other similarly situated
employees. No other compensation or bonuses of any kind will be paid for your
services during this period.


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3.       TERMINATION OF EMPLOYMENT EFFECTIVE FEBRUARY 15, 2002.

         Effective February 15, 2002, your employment at Corsair and Lightbridge
will be terminated and all your benefits will end. You will not be entitled to
receive any bonuses for the 2001 or 2002 years.

4.       SEVERANCE PAY EFFECTIVE FEBRUARY 16, 2002 TO JUNE 30, 2002.

         Corsair will pay you severance pay (less required deductions) at your
base rate of pay for the severance period from February 16, 2002 through June
30, 2002.

5.       STOCK OPTIONS.

         Your stock option grants will continue to vest in accordance with their
terms until February 15, 2002, provided that you continue to be employed as set
forth herein. Your rights concerning stock options continue to be governed by
the terms of the applicable plans and agreements.

6.       PAYMENT FOR ACCRUED VACATION, COBRA NOTIFICATION AND SUBSIDY
         AND 401(K).

         On or before February 15, 2002, you will be paid for any accrued but
unused vacation pay or paid time off, as the case may be.

         You will also be provided with COBRA notices and forms on or about that
date in order for you have the option to elect the continuation of your group
health, dental and vision insurance coverage after February 15, 2002. If you or
any of your family members elect to continue COBRA coverage after February 15,
2002, Corsair will continue to pay the same share of premiums for such coverage
(subject to annual rate adjustments) as if you were still an employee of Corsair
through June 30, 2002. If you or any of your family members elect to continue
this coverage after June 30, 2002, you will be responsible for all of the
premium payments.

         Lightbridge will also provide for the vesting at the appropriate time
under the 401(K) plan of the unvested company match to your 401(K) plan through
the date of termination of your employment.

7.       CONFIDENTIALITY AGREEMENT.

         You agree and acknowledge that the attached Proprietary Information and
Inventions Agreement which is incorporated herein by reference, remains in
effect after the termination of your employment according to the terms set forth
in that agreement.

8.       RETURN OF PROPERTY.

         On or before February 15, 2001, you will return to Corsair or
Lightbridge all documents, tapes, notes and other information and materials (and
all copies) in your possession which contain confidential information, whether
relating to Corsair or Lightbridge or any of their respective customers. You
will also return to Corsair or Lightbridge any credit cards, keys, and all other
property


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of Corsair or Lightbridge, except that you may keep the personal
computer that was provided to you by the companies.

9.       WAIVER AND RELEASE OF CLAIMS.

         In exchange for the continuation of your employment, the severance
payments made under Section 4 above and other valuable consideration from
Corsair or Lightbridge, the sufficiency of which is hereby acknowledged, on your
own and that on behalf of your heirs, personal representatives, and assigns, you
hereby voluntarily and irrevocably release, acquit and forever discharge Corsair
and Lightbridge, and all of Corsair and Lightbridge's affiliated and related
entities, and their officers, directors, agents, representatives, attorneys,
servants, employees, predecessors, successors, and assigns from any and all
claims, demands, liabilities, debts, judgments, damages, expenses, actions,
causes of action or suits of any kind whatsoever which you or your heirs,
personal representatives and assigns, and each of them, may have had or may now
have, whether known or unknown, including, but not limited to, common law
claims, statutory claims, claims for wages or earnings or benefits, claims for
overtime, claims or causes of action under the Civil Rights Act, the Employee
Retirement Income Security Act, the Fair Labor Standards Act, the American with
Disabilities Act, the Older Workers Benefit Protection Act, the Family and
Medical Leave Act, the Age Discrimination and Employment Act, the Equal Pay Act,
the California Fair Employment and Housing Act, the California Family Rights
Act, the California Labor code, the Worker Adjustment and Retraining
Notification Act, tort law, contract law, plant closing laws, law of wrongful
discharge, discrimination, harassment, fraud, misrepresentation, defamation,
libel, emotional distress, breach of the implied covenant of good faith and fair
dealing, any other federal, state or municipal statute or ordinance, and claims
or causes of action under any other theory, which arise out of or are related in
any way, directly or indirectly, with your employment by Corsair or Lightbridge
or your termination of such employment. You acknowledge that through this
Agreement you are receiving consideration from Corsair and Lightbridge beyond
that to which you would otherwise be entitled.

10.       NON-DISPARAGEMENT, NON- SOLICITATION.

         Each party agrees not to make any negative or disparaging statements or
comments about the other party, its affiliates and their related persons and
entities, as the case may be, to any person, entity or organization.

         As long as I am employed or engaged by Corsair and/or Lightbridge and
for the severance period, I shall not divert or attempt to divert from
Lightbridge and/or Corsair the business or patronage of any of the clients,
customers or accounts or prospective clients, customers or accounts that were
served or solicited by me while employed by the Corsair or Lightbridge.


11.      OPPORTUNITY FOR LEGAL REVIEW.

         You have been advised by Corsair and Lightbridge to consult with an
attorney prior to entering into this Agreement and you acknowledge that you have
had full opportunity to do so. In entering into this Agreement, you acknowledge
that you are not relying on any statement, representation or promise by Corsair
or Lightbridge or any representative of Corsair or Lightbridge, which is not
expressly set forth herein.


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12.      CONFIDENTIALITY.

         Each party agrees to keep the terms of this Agreement confidential and
to disclose them to no one except, (i) in the case of Mr. Meyer, to members of
his immediate family (who have agreed to be bound by the same confidentiality
obligations as he is), (ii) in the case of the Corsair or Lightbridge, to their
respective employees who have a need to know and who are bound by obligations of
confidentiality, or (iii) as may be reasonably necessary for the purpose of
obtaining professional advice, meeting legal reporting requirements, or pursuant
to judicial process, court order or subpoena.

13.      MISCELLANEOUS.

              a. SEVERABILITY. If any provision of this Agreement or the
application thereof is held invalid, the invalidity shall not affect other
provisions or applications of the Agreement which can be given effect without
the invalid provisions or application, and to this end this Agreement is
declared to be severable.

              b. WITHHOLDING. Compensation and benefits paid to you under this
Agreement will be reduced by all federal, state, local and other withholdings or
similar taxes as required by law.

              c. ARBITRATION. The parties will submit all controversies, claims
and matters of difference in any way related to this Agreement, its performance
or breach, to arbitration, according to the rules and practices of the American
Arbitration Association from time to time in effect. Any awards in such
arbitration shall be final and binding on all parties. The arbitrator shall
allocate the costs of the arbitration in such manner, as she/he deems equitable.
The arbitrator may require the reimbursement of all or a portion of the
reasonable legal fees incurred by the prevailing party in the arbitration
proceeding and any legal proceedings, which are taken to enforce the arbitral
award. Any rights to trial by jury with respect to any claim or proceeding
related to, or arising out of, this Agreement are waived by you and Corsair and
Lightbridge; provided, however, that Corsair and Lightbridge each reserves the
right to court enforcement of the attached agreement referenced in Section 7
above in accordance with the terms set forth therein.

              d. ENTIRE AGREEMENT; MODIFICATIONS. (i) This Agreement together
with the Proprietary Information and Inventions Agreement attached is the entire
agreement between the parties with respect to the matters covered hereby, and
may be amended, modified, superseded or canceled, or its terms waived, only by a
written instrument executed by each party or, in the case of a waiver, by the
party waiving compliance. (ii) Failure of a party at any time to require
performance of any provision of this Agreement will not affect the right at a
later time to enforce the same. (iii) No waiver of a breach of this Agreement,
whether by conduct or otherwise, in any one or more instances will be construed
as a further or continuing waiver of the breach or of any other term of this
Agreement. (iv) This Agreement shall inure to the benefit of and be binding upon
the successors and assigns of the parties hereto.

              e. APPLICABLE LAW. This Agreement will be construed under and
governed by the laws of The Commonwealth of Massachusetts without regard or
reference to the rules of conflicts of law that would require the application of
the laws of any other jurisdiction.


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14.      REVIEW PERIOD.

         You acknowledge that you have been given 21 days to review and study
this Agreement prior to its execution (although you may choose to voluntarily
execute this Agreement earlier), and that you have the right to revoke this
Agreement within 7 days following its execution. You acknowledge that you have
had the opportunity and the time to discuss this Agreement with an attorney and
that you have been encouraged to do so by Corsair and Lightbridge, and that no
monies payable by Corsair or Lightbridge pursuant to the terms of this Agreement
shall be disbursed to you until the expiration of the time limits prescribed in
this paragraph. You acknowledge that you are executing this Agreement
voluntarily, free from duress or any undue pressure or influence, and with full
knowledge of its intent and terms.

15.      RE-EXECUTION AT TERMINATION.

         Upon the termination of your employment, you agree to execute this
Agreement and Release again with a then current date.

         THIS AGREEMENT CONTAINS A RELEASE OF KNOWN AND UNKNOWN CLAIMS. You
acknowledge that you have read and understand Section 1542 of the California
Civil Code which reads: "A general release does not extend to claims which the
creditor does not know or suspect to exist in his favor at the time of executing
the release, which if known by him must have materially affected his settlement
with the debtor." You expressly waive and relinquish all right and benefits
under that section and under the law of any jurisdiction of similar effect with
respect to your release of any unknown or unsuspected claims that you may have
against Corsair or Lightbridge, their respective affiliates, and the entities
and persons specified above.

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

CORSAIR COMMUNICATIONS, INC.                Thomas Meyer


By: /s/ Pamela D.A. Reeve                   /s/ Thomas Meyer


LIGHTBRIDGE, INC.


By: /s/ Pamela D.A. Reeve