<PAGE>   1
                                                                   EXHIBIT 10.10


                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN




                               Agere Systems Inc.
                                       and
                   Such of its Subsidiary Companies which are
                             Participating Companies

                          Effective __________ __, 2001
<PAGE>   2
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN


                                TABLE OF CONTENTS


<TABLE>
<S>                                                                                                                   <C>
1.   INTRODUCTION AND PURPOSE....................................................................................      1
2.   DEFINITIONS.................................................................................................      1
3.   EXCESS RETIREMENT BENEFIT...................................................................................      3
     3.1.PARTICIPATION...........................................................................................      3
     3.2.AMOUNT OF EXCESS RETIREMENT BENEFIT.....................................................................      4
     3.3.NO SURVIVING SPOUSE OR DESIGNATED BENEFICIARY...........................................................      4
     3.4.FUTURE BENEFIT ADJUSTMENTS..............................................................................      4
     3.5.DETERMINATION OF BENEFIT................................................................................      4
     3.6.RELATIONSHIP TO OTHER PLANS.............................................................................      5
4.   MINIMUM RETIREMENT OR SURVIVOR BENEFITS.....................................................................      5
     4.1.PARTICIPATION...........................................................................................      5
     4.2.MINIMUM RETIREMENT BENEFIT..............................................................................      5
     4.3.SURVIVOR BENEFIT........................................................................................      5
5.   BENEFIT PAYMENTS............................................................................................      6
     5.1.COMMENCEMENT AND FORM OF BENEFITS.......................................................................      6
     5.2.FUTURE INCREASES........................................................................................      6
     5.3.TREATMENT DURING SUBSEQUENT EMPLOYMENT..................................................................      6
     5.4.MANDATORY PORTABILITY AGREEMENT.........................................................................      7
     5.5.FORFEITURE OF BENEFITS..................................................................................      7
6.   DISPOSITION OF PARTICIPATING COMPANY........................................................................      8
     6.1.SALE, SPIN-OFF, OR OTHER DISPOSITION OF PARTICIPATING COMPANY...........................................      8
7.   SOURCE OF PAYMENT...........................................................................................      8
     7.1.SOURCE OF PAYMENTS......................................................................................      8
     7.2.UNFUNDED STATUS.........................................................................................      8
     7.3.FIDUCIARY RELATIONSHIP..................................................................................      9
8.   ADMINISTRATION OF THE PLAN..................................................................................      9
     8.1.ADMINISTRATION..........................................................................................      9
     8.2.INDEMNIFICATION.........................................................................................      9
     8.3.CLAIMS PROCEDURE........................................................................................      9
     8.4.NAMED FIDUCIARIES.......................................................................................     10
     8.5.ROLE OF THE COMMITTEE...................................................................................     10
     8.6.ALLOCATION OF RESPONSIBILITIES..........................................................................     10
     8.7.MULTIPLE CAPACITIES.....................................................................................     10
9.   AMENDMENT AND TERMINATION...................................................................................     10
     9.1.AMENDMENT AND TERMINATION...............................................................................     10
10.  GENERAL PROVISIONS..........................................................................................     11
     10.1.    BINDING EFFECT.....................................................................................     11
     10.2.    NO GUARANTEE OF EMPLOYMENT.........................................................................     11
     10.3.    TAX WITHHOLDING....................................................................................     11
     10.4.    ASSIGNMENT OF BENEFITS.............................................................................     11
     10.5.    FACILITY OF PAYMENT................................................................................     11
     10.6.    SEVERABILITY.......................................................................................     12
     10.7.    PLAN YEAR..........................................................................................     12
     10.8.    HEADINGS...........................................................................................     12
     10.9.    GOVERNING LAW......................................................................................     12
     10.10.   ENTIRE PLAN........................................................................................     12
</TABLE>


                                      -i-
<PAGE>   3
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN

                               AGERE SYSTEMS INC.
                            SUPPLEMENTAL PENSION PLAN

                       Adopted Effective _______ __, 2001


                                     ARTICLE
                                       1.
                            INTRODUCTION AND PURPOSE


         The Agere Systems Inc. Supplemental Pension Plan (the "Plan") is
intended to constitute both (i) an unfunded "excess benefit plan" as defined in
ERISA Section 3(36), and (ii) an unfunded plan maintained primarily for the
purpose of providing deferred compensation and pension benefits for a select
group of management or highly compensated employees for purposes of Title I of
the Employee Retirement Income Security Act of 1974, as amended.

         The Plan is intended to reward participants who have provided the
Company with dedicated service during their employment and who, after
termination of employment with the Company, continue to acknowledge a duty of
loyalty to the Company and refrain from engaging in activities that are in
conflict with or adverse to the interests of the Company. Such restrictions are
necessary and reasonable to protect the Company's highly confidential and
proprietary information, valuable goodwill, customer relationships and
competitive position.

         The Plan is a successor to the Lucent Technologies Inc. Supplemental
Pension Plan, which is a predecessor plan of the Plan.

         Participation in the Mid-Career Pension Benefit described in Appendix A
shall be limited to these individuals categorized by the Company under the
predecessor plan as Participants and Employees, within the meaning of Appendix
A, as of December 31, 2000.

                                     ARTICLE
                                       2.
                                   DEFINITIONS

         Unless the context clearly indicates otherwise, the following terms
have the meanings described below when used in this Plan and references to a
particular Article or Section shall mean the Article or Section so delineated in
this Plan.

ACCOUNT BALANCE PROGRAM. The account balance program provisions of the
Retirement Income Plan, applicable generally to eligible employees hired after
December 31, 1998.

ADMINISTRATOR. The Pension Plan Administrator under the Retirement Income Plan,
or such other person or entity designated by the Company.

AFFILIATED CORPORATION. Any corporation of which more than 50 percent of the
voting stock is owned directly or indirectly by the Company.

ANNUAL BASIC PAY. For purposes of determining the Minimum Retirement Benefit and
Survivor Benefit under Article 4, the annual base salary rate on the last day
the Participant was on the active payroll plus an amount equal to the
Participant's target award, as determined under the Short Term Plan, in effect
at the time of the Participant's retirement, termination of employment or death.

BENEFIT LIMITATION. The maximum benefit payable to a Participant under the
Retirement Income Plan or the Pension Plan in accordance with Code
Sections 415(b) and (e), but after application of the Compensation
Limitation, if any, under the Retirement Income Plan or the Pension Plan.

BOARD. The Board of Directors of the Company.
<PAGE>   4
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN


CODE. The Internal Revenue Code of 1986, as amended from time to time. Any
reference to a particular section of Code includes any applicable regulations
promulgated under that section.

COMMITTEE. The Agere Employee Benefits Committee.

COMPANY. Agere Systems Inc., a Delaware Corporation, or its successor.

COMPENSATION. "Compensation" shall have the meaning set forth in the Retirement
Income Plan or the Pension Plan, as applicable, modified as set forth in this
Plan.

COMPENSATION LIMITATION. The maximum amount of annual compensation under Code
Section 401(a)(17) that may be tAKen into account in any Plan Year for benefit
accrual purposes under the Retirement Income Plan or the Pension Plan.

DISABILITY or DISABLED. "Disability" or "Disabled" shall have the meaning set
forth in the Agere Long Term Disability Plan for Management Employees.

ERISA. The Employee Retirement Income Security Act of 1974, as amended from time
to time. Any reference to a particular section of ERISA includes any applicable
regulations promulgated under that section.

INTERCHANGE AGREEMENT. "An Interchange Agreement" within the meaning of the
Retirement Income Plan and the Pension Plan.

INTERCHANGE COMPANY. An "Interchange Company" within the meaning of the
Retirement Income Plan and the Pension Plan.

LAWFUL SPOUSE. A person who is recognized as the lawful husband or lawful wife
of a Participant under the laws of the state of the Participant's domicile, and
who is a person whose consent is required pursuant to Section 417(a)(2)(A)(i) of
the Code for purposes of an election under Section 417(a)(1)(A)(i) of the Code.

LONG TERM PLAN. The Agere Systems Inc. 2001 Long Term Incentive Program, any
other Agere stock option plan, or a predecessor long term incentive plan.

MPA. The Mandatory Portability Agreement, effective January 1, 1985, between and
among AT&T, Former Affiliates and certain other companies and which, in
accordance with section 559 of the Tax Reform Act of 1984, provides for the
mutual recognition of service credit and the transfer of benefit obligations for
specified employees who terminate employment with one company signatory to such
agreement and subsequently commence employment with another company signatory to
such agreement.

NORMAL RETIREMENT AGE. "Normal Retirement Age" shall have the meaning set forth
in the Retirement Income Plan or the Pension Plan, as applicable.

OFFICER. An employee of a Participating Company holding a position evaluated or
classified above the "Executive" level by the Company, except that no employee
who is assigned to such a position on a temporary basis after being notified in
writing of the temporary status of such assignment shall be an "Officer" for any
purpose under this Plan.

PARTICIPANT. An individual who qualifies for an Excess Retirement Benefit under
Article 3, a Minimum Retirement or Survivor Benefit under Article 4, or a
Mid-Career Pension Benefit under Appendix A.

PARTICIPATING COMPANY. The Company and each of its subsidiaries that is a
Participating Company for purposes of the Retirement Income Plan or the Pension
Plan.

PENSION PLAN. The Agere Pension Plan, as amended from time to time.


                                      -2-
<PAGE>   5
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN


PLAN. This Agere Supplemental Pension Plan.

RETIREMENT INCOME PLAN. The Agere Retirement Income Plan, as amended from time
to time, including the Service-Based Program and the Account Balance Program
thereunder.

SERVICE-BASED PROGRAM. The service-based program provisions of the Retirement
Income Plan, applicable generally to eligible employees hired before January 1,
1999.

SHORT TERM AWARD. The actual amount awarded (including any amounts deferred
pursuant to the Agere Deferred Compensation Plan) annually to a Participant
pursuant to the Agere Short Term Incentive Plan or predecessor short term
incentive plans. Notwithstanding any other provision in this paragraph to the
contrary, Short Term Awards, for purposes of the Plan, shall not include any
amount paid or credited to a Participant in January, 1999. Furthermore, such
awards shall not include any payments paid to a Participant in the form of
Compensation or in lieu of Compensation after termination of employment except
that the Committee may make reasonable assumptions, to be applied uniformly,
regarding the amount of such payments to be included in the Short Term Award.
Once made, any such decision of the Committee shall be conclusive and not
subject to further review.

SHORT TERM PLAN. The Agere Systems Inc. Short Term Incentive Plan or predecessor
short term incentive plans covering Officers.

SUBSIDIARY. Any corporation as to which more than 80% of the voting stock is
owned directly or indirectly by the Company.

SURVIVING SPOUSE. A deceased Participant's surviving Lawful Spouse who is
eligible to receive a survivor annuity benefit under the Retirement Income Plan
or the Pension Plan.

TERM OF EMPLOYMENT. "Term of Employment" shall have the meaning set forth in the
Retirement Income Plan or the Pension Plan, as applicable, except that for all
purposes under the Mid-Career Pension Benefit, "Term of Employment" shall have
the meaning set forth in Appendix A.

TRANSFERRED INDIVIDUAL. A "Transferred Individual" within the meaning of the
Employee Benefits Agreement between Lucent and the Company dated as of February
1, 2001.

                                     ARTICLE
                                       3.
                            EXCESS RETIREMENT BENEFIT

3.1.     PARTICIPATION

         "Participant" for purposes of the Excess Retirement Benefit under this
Article 3 shall mean an individual who is a Participant, Surviving Spouse or
designated beneficiary under either the Retirement Income Plan or the Pension
Plan if such individual's benefit payable under the Retirement Income Plan or
the Pension Plan is limited by reason of the application of the Benefit
Limitation and/or the Compensation Limitation.

3.2.     AMOUNT OF EXCESS RETIREMENT BENEFIT

         (a) The amount, if any, of the Excess Retirement Benefit payable to a
Participant, Surviving Spouse or designated beneficiary shall be equal to the
excess of (i) over (ii), where:

                  (i) is the Participant's, Surviving Spouse's or designated
         beneficiary's pension benefit determined in accordance with the
         provisions of the Retirement Income Plan or the Pension Plan, except
         that for purposes of determining the Excess Retirement Benefit, the
         Benefit Limitation and the Compensation Limitation shall be disregarded
         and the amount of the Short


                                      -3-
<PAGE>   6
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN


         Term Award and any deferrals of salary or Short Term Award credited
         under the Agere Deferred Compensation Plan shall be included in
         Compensation; and

                  (ii) is the amount of the pension benefit actually payable to
         such Participant, Surviving Spouse or designated beneficiary under the
         Retirement Income Plan or the Pension Plan.

         (b) The amount of the Excess Retirement Benefit payable as a result of
the application of the Benefit Limitation under the Retirement Income Plan or
the Pension Plan shall be determined based upon the Retirement Income Plan or
the Pension Plan formula, as applicable, in effect (i) as of the date when
benefits are to commence; or (ii) for benefits payable in the form of an
annuity, as of the effective date of any subsequent increases or decreases in
the Benefit Limitation, and as of the effective date of any special increases in
the monthly benefit payable, prior to application of the Benefit Limitation, as
a result of amendments to the Retirement Income Plan or the Pension Plan,
whichever is applicable. Further, the amount of the Excess Retirement Benefit
shall be reduced for commencement of the Excess Retirement Benefit prior to the
date when the sum of the Participant's completed years and months of age and
Term of Employment is less than 75 years and/or for the cost of the survivor
annuity, if any, in the same manner as is set forth in the Retirement Income
Plan or the Pension Plan, as applicable.

3.3.     NO SURVIVING SPOUSE OR DESIGNATED BENEFICIARY

         If a Participant dies before the date as of which his or her benefit
commences under the Service-Based Program or the Pension Plan, and he or she
does not have a Surviving Spouse or designated beneficiary under such plan on
his or her date of death, no Excess Retirement Benefit shall be paid with
respect to such Participant. If the Participant dies before the date as of which
his or her benefit commences under the Account Balance Program, the Excess
Retirement Benefit shall be paid to the surviving spouse, if any; if there is no
surviving spouse such benefit shall be paid to the beneficiary or beneficiaries
designated under the Retirement Income Plan or, if there is no such designated
beneficiary, to the Participant's estate.

3.4.     FUTURE BENEFIT ADJUSTMENTS

         If a Participant has commenced receiving a service or disability
pension under the Retirement Income Plan or the Pension Plan in the form of a
joint and survivor annuity and his or her designated annuitant subsequently
predeceases him or her, the Participant's Excess Retirement Benefit under this
Article 3 shall be calculated in accordance with Section 3.2 and thereafter
paid, prospectively, by restoring the original cost of the joint and survivor
annuity form of benefit under the Retirement Income Plan or the Pension Plan,
whichever is applicable. Such adjustment shall be effective as of the first day
of the first month following the death of the designated annuitant.

3.5.     DETERMINATION OF BENEFIT

         Excess Retirement Benefit payments under this Article 3 shall be
calculated in accordance with the rules, procedures, and assumptions utilized
under the Retirement Income Plan or the Pension Plan, whichever is applicable.
Thus, whenever it is necessary to determine whether one benefit is less than,
equal to, or larger than another, or to determine the equivalent actuarial value
of any benefit, whether or not such form of benefit is provided under this Plan,
such determination shall be made, at the Administrator's discretion, by the
Company's enrolled actuary, using mortality, interest and other assumptions
normally used at the time in determining actuarial equivalence under the
Retirement Income Plan or Pension Plan, whichever is applicable.

3.6.     RELATIONSHIP TO OTHER PLANS

         The Excess Retirement Benefit payable under this Article 3 shall be in
addition to any other benefits provided, directly or indirectly, to a
Participant, Surviving Spouse or designated beneficiary by any Participating
Company. Participation in the Plan shall not preclude or limit the participation
of the Participant in any other benefit plan sponsored by a Participating
Company for which such Participant


                                      -4-
<PAGE>   7
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN


would otherwise be eligible. The Excess Retirement Benefit payable to a
Participant, Surviving Spouse or designated beneficiary under this Plan shall
not duplicate benefits payable to such Participant, Surviving Spouse or
designated beneficiary under any other plan or arrangement of a Participating
Company or any Affiliated Corporation.

                                     ARTICLE
                                       4.
                     MINIMUM RETIREMENT OR SURVIVOR BENEFITS

4.1.     PARTICIPATION

         "Participant" for purposes of the Minimum Retirement Benefit under
Section 4.2 shall mean (1) an Officer or a former employee of a Participating
Company who was an Officer on the last day of employment, if such individual is
retired on a service pension under the Retirement Income Plan, (2) an Officer
whose Term of Employment has been five years or more, is not Disabled, and who
terminates employment on or after his or her sixty-second birthday.

         "Participant" for purposes of the Survivor Benefit under Section 4.3
shall mean an Officer, or a former employee of a Participating Company who was
an Officer on the last day of employment, if such former employee (1) is
Disabled or (2) is eligible to receive a Minimum Retirement Benefit under this
Article 4 of the Plan.

4.2.     MINIMUM RETIREMENT BENEFIT

         A Participant shall be eligible to receive an annual minimum retirement
benefit payable monthly, equal to 15% of the Participant's Annual Basic Pay on
the last day the Participant was on the active payroll reduced by the sum of the
following benefits received by the Participant which are attributable to the
period for which benefits are provided under this Section 4.2: a service pension
or deferred vested pension under the Retirement Income Plan or Pension Plan, an
Excess Retirement Benefit under Article 3, a Mid-Career Pension Benefit under
Appendix A, and by any other retirement income payments received by the
Participant from his or her Participating Company or from a Successor or
Predecessor Plan Sponsor. However, no reduction shall be made on account of any
pension under the Retirement Income Plan at a rate greater than the rate of such
pension on the date the Participant first received such pension after his or her
retirement or other termination of employment, and no reduction shall be made on
account of an Excess Retirement Benefit under Article 3, or a Mid-Career Pension
Benefit under Appendix A, at a rate greater than the rate of such benefit, as of
first date the Participant was entitled to receive such benefit after his or her
retirement or other termination of employment.

4.3.     SURVIVOR BENEFIT

         In the event of the death of a Participant, the Surviving Spouse of
such Participant shall be eligible to receive an annual benefit, payable
monthly, equal to 15 percent of the Participant's Annual Basic Pay on the last
day the Participant was on the active payroll prior to his or her death reduced
by the sum of the following benefits received by the Participant's Surviving
Spouse on account of the death of the Participant and which are attributable to
the period for which benefits are provided under this Section 4.3: an
annuitant's pension under the Retirement Income Plan or Pension Plan (or the
actuarial equivalent thereof in the event of a lump sum payment), an annuitant's
Excess Retirement Benefit under Article 3, and any lifetime payments to such
Surviving Spouse from the Participant's Participating Company or from any
Successor Plan Sponsor. However, no reduction shall be made on account of an
annuitant's pension under the Retirement Income Plan or an annuitant's Excess
Retirement Benefit under Article 3 at a rate greater than (1) the rate of such
pension or annuity on the date such pension or annuity was first payable in the
case of the death of a Participant who is on the active payroll or (2) the rate
of such pension or annuity on the date such pension or annuity first would have
been payable had the Participant died on the day after the last day the
Participant was on the active payroll in the case of the death of a Participant
who is not on the active payroll.

4.4.     DETERMINATION OF BENEFIT


                                      -5-
<PAGE>   8
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN


         Minimum Retirement Benefit and Survivor Benefit payments under this
Article 4 shall be calculated in accordance with the rules, procedures, and
assumptions utilized under the Retirement Income Plan or the Pension Plan,
whichever is applicable. Thus, whenever it is necessary to determine whether one
benefit is less than, equal to, or larger than another, or to determine the
equivalent actuarial value of any benefit, whether or not such form of benefit
is provided under this Plan, such determination shall be made, at the
Administrator's discretion, by the Company's enrolled actuary, using mortality,
interest and other assumptions normally used at the time in determining
actuarial equivalence under the Retirement Income Plan or Pension Plan,
whichever is applicable.

                                     ARTICLE
                                       5.
                                BENEFIT PAYMENTS

5.1.     COMMENCEMENT AND FORM OF BENEFITS

         Any benefit provided under this Plan payable to a Participant,
Surviving Spouse or designated beneficiary (i) shall commence at the same time,
(ii) shall be paid for as long as and (iii) shall be paid in the same benefit
form as the Participant's, Surviving Spouse's or beneficiary's benefits are paid
under the Retirement Income Plan or the Pension Plan, whichever is applicable,
provided, however, that the Committee shall have the right to approve the
Participant's election of the form of the Excess Retirement Benefit under
Article 3 payable to the Participant. In addition, the joint and survivor
annuity or the ten-year certain benefit option form shall not be available to
Participants eligible for a Mid-Career Pension Benefit under Appendix A for that
portion of the benefit under this Plan.

5.2.     FUTURE INCREASES

         If an amendment to the Retirement Income Plan is made in respect of a
Participant who did not elect a lump sum payment under the Retirement Income
Plan or to provide for an increase in the service pensions of previously retired
employees or an increase in the survivor annuities payable under the Retirement
Income Plan, then a Participant's, Surviving Spouse's or designated
beneficiary's benefit under this Plan, as applicable, shall be increased
pursuant to the same terms and conditions as are set forth in such Retirement
Income Plan amendment, except that any such increase shall apply only to the
Surviving Spouse or designated beneficiary benefit related to a deceased
Participant who terminated employment or died on or prior to the effective date
of such amendment.

5.3.     TREATMENT DURING SUBSEQUENT EMPLOYMENT

         Notwithstanding any other provision of the Plan, a Participant's
employment or reemployment with any Participating Company or with any
Interchange Company (if the Employee is covered by the applicable Interchange
Agreement and, if applicable, has not waived coverage pursuant to the terms of
the Interchange Agreement) subsequent to retirement or termination of employment
with entitlement to a benefit under the Plan shall result in the permanent
suspension of payment of such benefit to the Participant for the period of such
employment or reemployment to the extent and in a manner consistent with the
terms and conditions applicable to the suspension of benefit payments under the
Retirement Income Plan or the Pension Plan, whichever is applicable. A
Participant's benefit shall recommence simultaneously with the recommencement of
his or her benefits under the Retirement Income Plan or the Pension Plan. The
amount of the Participant's benefit upon recommencement shall be adjusted to
reflect adjustments, if any, in the amount of the Participant's pension benefit
under the Retirement Income Plan or the Pension Plan resulting from the period
of reemployment. Following recommencement of payment, the Participant, Surviving
Spouse or designated beneficiary shall not be eligible to receive any benefit
payments that would otherwise have been payable but for the suspension.

5.4.     MANDATORY PORTABILITY AGREEMENT

         A Participant (i) who is employed by an "Interchange Company," as that
term is defined under the MPA, subsequent to retirement or termination of
employment from the Company, its subsidiaries or any


                                      -6-
<PAGE>   9
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN


Affiliated Corporation, (ii) who is covered under the terms and conditions of
the MPA, and (iii) for whom assets and liabilities are transferred from the
Retirement Income Plan or the Pension Plan, shall forfeit his rights to a
benefit under the Plan, including the rights of the Participant's Surviving
Spouse and beneficiaries to a benefit under this Plan.

5.5.     FORFEITURE OF BENEFITS

         Notwithstanding any eligibility or entitlement to benefits of a
Participant arising or conferred under any other provision or paragraph of this
Plan, all benefits for which a Participant would otherwise be eligible hereunder
shall be forfeited under the following circumstances:

         (a)      (i) the Participant is discharged by a Participating Company
for cause. For purposes of this Plan, cause shall mean:

                  (A)      the Participant's conviction (including a plea of
                           guilty or nolo contendere) of a felony or any crime
                           of theft, dishonesty or moral turpitude;

                  (B)      gross omission or gross dereliction of any statutory
                           or common law duty of loyalty to the Company; or

                  (C)      violation of Agere's Business Guideposts - the
                           Company's Code of Conduct.

                  (ii)determination by the Board or its delegate that the
Participant engaged in misconduct in connection with the Participant's
employment with a Participating Company or with any other entity of which the
Company has an ownership interest; or

         (b) the Participant without the Company's consent both during and after
termination for any reason of employment with a Participating Company, on behalf
of any competitor of the Company (A) renders any service relating to (1)
strategic planning, research and development, manufacturing, marketing, or
selling with respect to any product, process, material or service which
resembles, competes with, or is the same as a product, process, material or
service of the Company about which such Participant gained any proprietary or
confidential information or on which such Participant worked prior to his
termination of employment, or (2) any actual or potential customer of the
Company about whom the Participant gained any proprietary or confidential
knowledge or with whom such Participant worked prior to his termination of
employment; and (B) solicits or offers, or induces or encourages others to
solicit or offer, employment to any employee of the Company, provided, however,
that the portion of the Excess Retirement Benefit accrued prior to December 31,
1997 shall not be subject to the provisions of this Section 5.5(b).

                                     ARTICLE
                                       6.
                      DISPOSITION OF PARTICIPATING COMPANY

6.1.     SALE, SPIN-OFF, OR OTHER DISPOSITION OF PARTICIPATING COMPANY

         (a) Subject to Section 10.1, in the event the Company sells, spins off,
or otherwise disposes of a Subsidiary or an Affiliated Corporation, or disposes
of all or substantially all of the assets of a Subsidiary or an Affiliated
Corporation such that one or more Participants terminate employment for the
purpose of accepting employment with the purchaser of such stock or assets, any
person employed by such Subsidiary or Affiliated Corporation who ceases to be an
employee as a result of the sale, spin-off, or disposition shall be deemed to
have terminated his or her employment with a Participating Company and be
eligible for a benefit under this Plan commencing at the same time as his or her
benefit, if any, commences under the Retirement Income Plan or the Pension Plan.

         (b) Notwithstanding the foregoing provisions of this Section 6.1, and
subject to Section 10.1, if, as part of the sale, spin-off, or other disposition
of the stock or assets of a Subsidiary or Affiliated Corporation, the Subsidiary
or Affiliated Corporation, its successor owner, or any other party agrees in


                                      -7-
<PAGE>   10
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN


writing to assume the liability for the payment of any of the benefits under
this Plan to which the Participant, Surviving Spouse and/or designated
beneficiary would have been entitled under the Plan but for such sale, spin-off,
or other disposition, then the entitlement of the Participant, his or her
Surviving Spouse or beneficiary to any such benefits under this Plan shall
terminate. Any subsequent entitlement of the former Participant, his or her
Surviving Spouse or beneficiary to such benefits shall be the sole
responsibility of the assuming party.

                                     ARTICLE
                                       7.
                                SOURCE OF PAYMENT

7.1.     SOURCE OF PAYMENTS

         Benefits arising under this Plan and all costs, charges, and expenses
relating thereto will be payable from the Company's general assets. The Company
may, however, establish a trust to pay such benefits and related expenses,
provided such trust does not cause the Plan to be "funded" within the meaning of
ERISA. To the extent trust assets are available, they may be used to pay
benefits arising under this Plan and all costs, charges, and expenses relating
thereto. To the extent that the funds held in the trust, if any, are
insufficient to pay such benefits, costs, charges and expenses, the Company
shall pay such benefits, costs, charges, and expenses from its general assets.

7.2.     UNFUNDED STATUS

         The Plan at all times shall be entirely unfunded for purposes of the
Code and ERISA and no provision shall at any time be made with respect to
segregating any assets of a Participating Company for payment of any benefits
hereunder. Funds that may be invested through a trust described in Section 7.1
shall continue for all purposes to be part of the general assets of the
Participating Company which invested the funds. The Plan constitutes a mere
promise by the Company and the Participating Companies to make benefit payments,
if any, in the future. No Participant, Surviving Spouse, beneficiary or any
other person shall have any interest in any particular assets of a Participating
Company by reason of the right to receive a benefit under the Plan and to the
extent the Participant, Surviving Spouse, beneficiary or any other person
acquires a right to receive benefits under this Plan, such right shall be no
greater than the right of any unsecured general creditor of a Participating
Company.

7.3.     FIDUCIARY RELATIONSHIP

         Nothing contained in the Plan, and no action taken pursuant to the
provisions of the Plan, shall create or be construed to create a trust or a
fiduciary relationship between or among the Company, any other Participating
Company, the Board, the Administrator, the Committee, any Participant, any
Surviving Spouse, beneficiary or any other person, except as provided in Section
8.4.

                                     ARTICLE
                                       8.
                           ADMINISTRATION OF THE PLAN

8.1.     ADMINISTRATION

         The Company shall be the "plan administrator" of the Plan as that term
is defined in ERISA.

8.2.     INDEMNIFICATION

         Neither the Administrator, any member of the Board or of the Committee,
nor each other officer to whom any duty or power relating to the administration
or interpretation of the Plan may be allocated or delegated, shall be personally
liable by reason of any contract or other instrument executed by such individual
or on his or her behalf in his or her capacity as the Administrator or as a
member of the Board or of the Committee, nor for any mistake of judgment made in
good faith, and the Company shall indemnify and hold harmless the Administrator,
each member of the Board, each member of the Committee, and


                                      -8-
<PAGE>   11
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN


each other employee or officer to whom any duty or power relating to the
administration or interpretation of the Plan may be allocated or delegated,
against any cost or expense (including attorneys' fees) or liability (including
any sum paid in settlement of a claim) arising out of any act or omission to act
in connection with the Plan unless arising out of such person's own fraud or bad
faith.

8.3.     CLAIMS PROCEDURE

         (a) All claims for benefit payments under the Plan shall be submitted
in writing by the Participant, Surviving Spouse, Beneficiaries, or any
individual duly authorized by them (Claimant for purposes of this Section 8.3),
to the Administrator. The Administrator shall notify the Claimant in writing
within 90 days after receipt as to whether the claim has been granted or denied.
This period may be extended for up to an additional 90 days in unusual cases
provided that written notice of the extension is furnished to the Claimant prior
to the commencement of the extension. In the event the claim is denied, such
notice shall (i) set forth the specific reasons for denial, (ii) make reference
to the pertinent Plan provisions on which the denial is based, (iii) describe
any additional material or information necessary before the Claimant's request
may be acted upon, and (iv) explain the procedure for appealing the adverse
determination.

         (b) Any Claimant whose claim for benefits has been denied, in whole or
in part, may, within 60 days of receipt of any adverse benefit determination,
appeal such denial to the Committee. All appeals shall be in the form of a
written statement and shall (i) set forth all of the reasons in support of
favorable action on the appeal, (ii) identify those provisions of the Plan upon
which the Claimant is relying, and (iii) include copies of any other documents
or materials which may support favorable consideration of the claim. The
Committee shall decide the issues presented within 60 days after receipt of such
request, but this period may be extended for up to an additional 60 days in
unusual cases provided that written notice of the extension is furnished to the
Claimant prior to the commencement of the extension. The decision of the
Committee shall be set forth in writing, include specific reasons for the
decision, refer to pertinent Plan provisions on which the decision is based, and
shall be final and binding on all persons affected thereby.

         Any Claimant whose claim for benefits has been denied shall have such
further rights of review as are provided in ERISA Section 503, and the Committee
and Administrator shall retain such right, authority, And discretion as is
provided in or not expressly limited by ERISA Section 503.

         (c) The Committee shall serve as the final review committee, under the
Plan and ERISA, for the review of all appeals by Claimants whose initial claims
for benefits have been denied, in whole or in part, by the Administrator. The
Committee shall have the authority to determine conclusively for all parties any
and all questions arising from administration of the Plan, and shall have sole
and complete discretionary authority and control to manage the operation and
administration of the Plan, including, but not limited to, authorizing
disbursements according to the Plan, the determination of all questions relating
to eligibility for participation and benefits, interpretation of all Plan
provisions, determination of the amount and kind of benefits payable to any
Participant, Surviving Spouse or Beneficiary, and the construction of disputed
and doubtful terms. Such decisions by the Committee shall be conclusive and
binding on all parties and not subject to further review.

8.4.     NAMED FIDUCIARIES

         The Company, the Committee, the Pension Plan Administrator(s) and each
Participating Company is each a named fiduciary as that term is used in ERISA
with respect to the particular duties and responsibilities herein provided to be
allocated to each of them.

8.5.     ROLE OF THE COMMITTEE

         (a) The Committee shall have the specific powers elsewhere herein
granted to it and shall have such other powers as may be necessary in order to
enable it to administer the Plan, except for powers herein granted or provided
to be granted to others.

         (b) The procedures for the adoption of by-laws and rules of procedure
and for the


                                      -9-
<PAGE>   12
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN


employment of a secretary and assistants shall be the same as are set forth in
the Retirement Income Plan or the Pension Plan.

8.6.     ALLOCATION OF RESPONSIBILITIES

         The Company may allocate responsibilities for the operation and
administration of the Plan consistent with the Plan's terms, including
allocation of responsibilities to the Committee and the other Participating
Companies. The Company and other named fiduciaries may designate in writing
other persons to carry out their respective responsibilities under the Plan, and
may employ persons to advise them with regard to any such responsibilities.

8.7.     MULTIPLE CAPACITIES

         Any person or group of persons may serve in more than one fiduciary
capacity with respect to the Plan.

                                     ARTICLE
                                       9.
                            AMENDMENT AND TERMINATION

9.1.     AMENDMENT AND TERMINATION

         Pursuant to ERISA Section 402(b)(3), the Board or its delegate (acting
pursuant to the Board's delegations of authority then in effect) may from time
to time amend, suspend, or terminate the Plan at any time. Plan amendments may
include, but are not limited to, elimination or reduction in the level or type
of benefits provided prospectively to any class or classes of Participants (and
any Surviving Spouse or designated beneficiary). Any and all Plan amendments may
be made without the consent of any Participant, Surviving Spouse or designated
beneficiary. Notwithstanding the foregoing, no such amendment, suspension, or
termination shall retroactively impair or otherwise adversely affect the rights
of any Participant, Surviving Spouse, beneficiary or other person to benefits
under the Plan, the Retirement Income Plan or the Pension Plan which have arisen
prior to the date of such action.

                                     ARTICLE
                                      10.
                               GENERAL PROVISIONS

10.1.    BINDING EFFECT

         The Plan shall be binding upon and inure to the benefit of each
Participating Company and its successors and assigns, and to each Participant,
his or her successors, designees, beneficiaries, designated annuitants, and
estate. The Plan shall also be binding upon any successor corporation or
organization succeeding to substantially all of the assets and business of the
Company. Nothing in the Plan shall preclude the Company from merging or
consolidating into or with, or transferring all or substantially all of its
assets to, another corporation which assumes the Plan and all obligations of the
Company hereunder. The Company agrees that it will make appropriate provision
for the preservation of the rights of Participants, Surviving Spouses and
beneficiaries under the Plan in any agreement or plan or reorganization into
which it may enter to effect any merger, consolidation, reorganization, or
transfer of assets. Upon such a merger, consolidation, reorganization, or
transfer of assets, the term "Participating Company" shall refer to such other
corporation and the Plan shall continue in full force and effect.

10.2.    NO GUARANTEE OF EMPLOYMENT

         Neither the Plan nor any action taken hereunder shall be construed as
(i) a contract of employment or deemed to give any Participant the right to be
retained in the employment of a Participating Company, the right to any level of
compensation, or the right to future participation in the Plan; or (ii)
affecting the right of a Participating Company to discharge or dismiss any
Participant at any time.


                                      -10-
<PAGE>   13
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN


10.3.    TAX WITHHOLDING

         The Company or a Participating Company, as applicable, shall withhold
all federal, state, local, or other taxes required by law to be withheld from
all benefit payments under the Plan.

10.4.    ASSIGNMENT OF BENEFITS

         No benefits under the Plan or any right or interest in such benefits
shall be assignable or subject in any manner to anticipation, alienation, sale,
transfer, claims of creditors, garnishment, pledge, execution, attachment or
encumbrance of any kind, including, but not limited to, pursuant to any domestic
relations order (within the meaning of ERISA Section 206(d)(3) and Code Section
414(p)(1)(B)) or judgment or CLaims for alimony, support, separate maintenance,
and claims in bankruptcy proceedings, and any such attempted disposition shall
be null and void.

10.5.    FACILITY OF PAYMENT

         If the Administrator shall find that any person to whom any amount is
or was payable under the Plan is unable to care for his or her affairs because
of illness or accident, then any payment, or any part thereof, due to such
person (unless a prior claim therefor has been made by a duly appointed legal
representative), may, if the Administrator so directs the Company, be paid to
the same person or institution that the benefit with respect to such person is
paid or to be paid under the Retirement Income Plan or Pension Plan, if
applicable, or the Participant's Lawful Spouse, a child, a relative, an
institution maintaining or having custody of such person, or any other person
deemed by the Administrator to be a proper recipient on behalf of such person
otherwise entitled to payment. Any such payment shall be in complete discharge
of the liability of the Company, the Board, the Committee, the Administrator,
and the Participating Company therefor. If any payment to which a Participant,
Surviving Spouse or beneficiary is entitled under this Plan is unclaimed or
otherwise not subject to payment to the person or persons so entitled, such
amounts representing such payment or payments shall be forfeited after a period
of two years from the date the first such payment was payable and shall not
escheat to any state or revert to any party; provided, however, that any such
payment or payments shall be restored if any person otherwise entitled to such
payment or payments makes a valid claim.

10.6.    SEVERABILITY

         If any section, clause, phrase, provision, or portion of this Plan or
the application thereof to any person or circumstance shall be invalid or
unenforceable under any applicable law, such event shall not affect or render
invalid or unenforceable the remainder of this Plan and shall not affect the
application of any section, clause, provision, or portion hereof to other
persons or circumstances.

10.7.    PLAN YEAR

         For purposes of administering the Plan, each plan year shall begin on
January 1 and end on December 31.

10.8.    HEADINGS

         The captions preceding the sections and articles hereof have been
inserted solely as a matter of convenience and shall not in any manner define or
limit the scope or intent of any provisions of the Plan.

10.9.    GOVERNING LAW

         The Plan shall be governed by the laws of the State of New Jersey
(other than its conflict of laws provisions) from time to time in effect, except
to the extent such laws are preempted by the laws of the United States of
America.

10.10.   ENTIRE PLAN


                                      -11-
<PAGE>   14
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN


         This written Plan document is the final and exclusive statement of the
terms of this Plan, and any claim of right or entitlement under the Plan shall
be determined in accordance with its provisions pursuant to the procedures
described in Article 8. Unless otherwise authorized by the Board or its
delegate, no amendment or modification to this Plan shall be effective until
reduced to writing and adopted pursuant to Section 9.1.


                                      -12-
<PAGE>   15
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN


         IN WITNESS WHEREOF, the Company has caused this Plan to be executed on
this ___ day of ___________, 2000.



                                           By:__________________________
                                              Vice President, Human Resources


Attest:



_______________________________
Vice President, General Counsel
and Secretary


                                      -13-
<PAGE>   16
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN


                                    APPENDIX
                                       A.
                           MID-CAREER PENSION BENEFIT

         (A)      PARTICIPATION

           An individual is a Participant for purposes of the Mid-Career Pension
  Benefit if (a) the individual was hired or rehired by a Participating Company
  (or, with respect to Transferred Individuals, a "Participating Company" under
  a predecessor plan) on or before July 16, 1997 and at age 35 or older, and (b)
  the individual was hired or rehired by a Participating Company (or, with
  respect to Transferred Individuals, a "Participating Company" under a
  predecessor Plan) at Director level or above, and (c) the individual's Term of
  Employment includes at least one year of continuous employment for a
  Participating Company (or, with respect to Transferred Individuals, a
  "Participating Company" under a predecessor Plan) at Director level or above,
  provided, however, that if an individual was hired or rehired by a
  Participating Company (or, with respect to Transferred Individuals, a
  "Participating Company" under a predecessor plan) on or after November 18,
  1981, such continuous employment was on a full-time basis (as classified by
  the Company), and (d) the individual is employed at Vice President level or
  above on December 31, 2000 and at the time of termination of employment;
  provided that "Participant" shall be limited to Participants identified in the
  records of the Company as of December 31, 2000.

           "Vice President level," formerly Executive level, E-Level, E-band,
  Fifth level and SG-12 through SG-14, shall mean the level directly above
  Director level, formerly D-band, or any equivalent salary grade or level as
  determined by the Company.

           No Mid-Career Pension Benefit in respect of a Participant shall be
  payable after the death of the Participant.

           (B)    ELIGIBILITY

           (1)    EMPLOYEE

           The word "Employee" shall mean for purposes of the Mid-Career Pension
  Benefit a Participant, as defined above, who has completed a term of
  employment of at least five years, classified by the Company as full-time, for
  one or more Participating Companies (including, with respect to term of
  employment before October 1, 2000, with "Participating Companies" under a
  predecessor plan) at Vice President level or above, prior to the last day of
  the month in which he or she reaches Normal Retirement Age, provided, however,
  that unless approved by the Board, or its delegate, an individual is not an
  Employee if:

           (i) the individual (ineligible to participate in this Plan because he
  or she was hired before age 35 and/or he or she was hired below Director
  level) terminates employment with a Participating Company, and is rehired by a
  Participating Company within one year of his or her termination of employment;

           (ii) the individual terminates employment with a company with which a
  Participating Company has an Interchange Agreement, and is hired by a
  Participating Company within one year of termination of employment, if the
  individual has not waived coverage pursuant to the terms of the applicable
  Interchange Agreement;

           (iii) the individual terminates employment with a company in which a
  Participating Company has an ownership interest, and is hired or rehired by a
  Participating Company within one year of termination of employment, unless he
  or she was a Participant in the Plan prior to employment with the Agere
  non-Controlled Group company or the nonparticipating Controlled Group company;
  or

           (iv) the individual is employed by a company which is acquired by a
  Participating Company.

           (2)    SERVICE AND DISABILITY BENEFIT


                                      -14-
<PAGE>   17
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN


                  Any Employee shall be eligible for a service benefit or a
  disability benefit if he or she is eligible for a service or a disability
  pension pursuant to the Service-Based Provisions of the Retirement Income
  Plan, including an Employee who is eligible for a service pension as the
  result of a Transition Leave of Absence or a Transition to Retirement as set
  forth in the Retirement Income Plan.

           (3)    DEFERRED BENEFIT

                  Any Employee is eligible for a deferred benefit if the
  Employee is vested under the Retirement Income Plan or the Pension Plan but is
  not eligible for either a service or a disability pension under the
  Service-Based Provisions of the Retirement Income Plan or under the Pension
  Plan.

           (C)    CALCULATION OF MID-CAREER PENSION BENEFIT AMOUNT

                  The annual benefit amount will equal:

                  A x B x C

           Where:

                  A  =     Mid-Career Pension Credits;
                  B  =     One-half of the Retirement Income Plan Base Formula
                           Multiplier; and
                  C  =     The sum of (i) Average Base Period Compensation
                           multiplied by Years of Service through the end of the
                           Base Period and (ii) Post-Base Period Compensation,
                           divided by total Term of Employment.

                  (I)      MID-CAREER PENSION CREDITS

           For purposes of determining A above, "Mid-Career Pension Credits" is
defined as:

           (i) For those employees hired or rehired at Vice President level or
  above, and all of whose Term of Employment is at Vice President level or
  above, Mid-Career Pension Credits is the difference between 35 years and the
  Term of Employment that could accrue if the employee worked to the later of
  Normal Retirement Age, retirement or termination of employment, provided that
  the Mid-Career Pension Credits shall not exceed the actual Term of Employment
  and shall not include any part-time service if the employee was hired by the
  Company on or after November 18, 1981.

           (ii) For those employees hired or rehired at Director level or above,
  and whose Term of Employment includes service at Director level or below,
  Mid-Career Pension Credits is computed by multiplying the employee's
  Mid-Career Pension Credits as defined in (i) above, by a fraction, the
  numerator of which shall be the number of years and months of service
  completed with a Participating Company (or, with respect to Transferred
  Individuals, a "Participating Company" under any predecessor plan) at Vice
  President level and above, and the denominator of which shall be the actual
  Term of Employment at termination of employment, provided, however, that for
  any Transferred Individual on the active roll of AT&T as of August 29, 1991,
  his or her benefit under this Plan shall equal the greater of the benefit
  calculated under the definition of Mid-Career Pension Credits in this
  subsection (ii) as of the Transferred Individual's retirement or termination
  of employment or the benefit accrued under a predecessor plan as of August 29,
  1991;

                  (II)     RETIREMENT INCOME PLAN BASE FORMULA MULTIPLIER

           For purposes of determining B above, the "Management Plan Base
  Formula Multiplier" shall be the numerical percentage which is multiplied by
  the Employee's average annual Compensation for the Base Period, in the
  calculation of the Employee's accrued pension benefit under the Retirement
  Income Plan.

           "Base Period" shall mean the pay base averaging period used to
  calculate the Employee's benefit under the Retirement Income Plan.


                                      -15-
<PAGE>   18
                  AGERE SYSTEMS INC. SUPPLEMENTAL PENSION PLAN


                  (III)    AVERAGE BASE PERIOD COMPENSATION

           For purposes of determining C above, "Average Base Period
  Compensation" shall be the Employee's average annual Compensation for the Base
  Period used in the calculation of the Employee's accrued benefit under the
  Retirement Income Plan, except that for purposes of determining the benefit
  amount hereunder, the Compensation Limitation shall be disregarded and the
  amount of the Short Term Award and any salary deferrals credited under the
  Agere Deferred Compensation Plan shall be included in Compensation.

                  (IV)     POST-BASE PERIOD COMPENSATION

           For purposes of determining C above, "Post-Base Period Compensation"
  shall be the Employee's Compensation after the Base Period used in the
  calculation of the Employee's accrued benefit under the Retirement Income
  Plan, except that for purposes of determining the benefit amount hereunder,
  the Compensation Limitation shall be disregarded and the amount of the Short
  Term Award and any salary deferrals credited under the Agere Deferred
  Compensation Plan shall be included in Compensation.


                                      -16-