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                                                                   Exhibit 10.23

                        [Letterhead of John T. Dickson]

December 15, 2000


Mark T. Greenquist
Lerchenbergstrasse 115
CH-8703 Erlenbach
Switzerland


Dear Mark:

It gives me great pleasure to offer you an Officer position with Agere Systems
Inc., formerly known as the Microelectronics Group of Lucent Technologies Inc.
(hereinafter "Agere" or the "Company"). In addition to confirming my offer, this
letter sets out the terms and conditions of your employment with Agere. It also
outlines the current major features of Agere's compensation and benefit plans
and practices.

As you are aware, Lucent has announced its intention to spin-off Agere into a
separate company initially through an IPO, which is expected to occur in the
first quarter of calendar 2001, with the actual spin-off currently scheduled for
later in calendar 2001. All of the plans referred to in this letter reflect the
current compensation and benefit plans that apply to Agere employees. It is
expected that Agere will initially adopt most of these plans, although many of
the decisions associated with compensation and employee benefit design post-spin
have not been finalized, and it is expected that changes will occur from the
current offerings.

ASSUMPTION OF DUTIES: We propose that effective on or about January 22, 2001,
you will assume the position of Executive Vice President and Chief Financial
Officer of Agere reporting to me. Your principal work location will be in
Allentown, Pennsylvania.

COMPENSATION COMPONENTS: The Company's fiscal year begins October 1 and ends
September 30. Currently, compensation consists of three components: Base Salary,
a Short Term Incentive Award, and Stock Option grants made under the Long Term
Incentive Program. These components are described below.

BASE SALARY: Your initial annual base salary will be $400,000. Employees are
paid monthly and based on a January 22, 2001 date of hire, you would receive
your first paycheck at the end of January and thereafter at the end of each
month. You will be eligible for a salary increase consideration 24 months from
hire.

SHORT TERM INCENTIVE AWARD: Your target bonus opportunity is 70% of your base
salary (i.e., 70% x $400,000 = $280,000). Above target performance would, of
course, yield above target compensation, consistent with Agere's
pay-for-performance philosophy. Short Term Awards for fiscal year 2001 are
payable in December 2001. Since you will be joining us after the beginning of
the fiscal year, your 2001 short term incentive award will be prorated for your
partial service during the fiscal year.

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Mark T. Greenquist
December 15, 2000
Page 2

STOCK OPTIONS: As an officer of Agere, you will be eligible to receive
non-qualified stock option grants under the Long Term Incentive Program
("LTIP"). The plan provides for supervisory assessment of your performance in
awarding options. As with the Short Term Incentive, Long Term Incentives are
closely linked to performance and with the Company's strategy to meet the
challenges of an ever-changing marketplace. The Company cannot guarantee
continuation of the LTIP in its current format, nor can it guarantee annual
grant levels to individual participants. At the IPO, Agere will adopt its own
Long Term Incentive Plan and it is currently expected that all stock option
grants to you will be made from that plan.

HIRING INCENTIVE: In order to encourage you to join Agere, and to address your
incentives you forfeit upon leaving your current employer, the Company will
provide you with the following:

-    We will ask the Stock Awards Committee to award you a stock option grant of
     300,000 Agere stock options at the IPO. The term of the option will be ten
     years, with vesting over a four-year period from the date of the grant as
     follows: 25% vests one year after the grant date and the remaining options
     vest monthly in equal mounts over the next 36 months. The option price will
     be equal to 100% of the Agere IPO price. The specific terms of your stock
     options will be contained in the Agere Long Term Incentive Plan document
     and in your individual Stock Option Agreement. You will receive your
     Agreement after the Committee approves your grant at the time of the IPO.

-    We will ask the Lucent Stock Awards Committee to approve a hiring grant of
     15,000 Lucent Restricted Shares effective on your first day of active
     employment. Vesting will be 20% annually over a five-year period. The first
     vesting will occur 1 year after the grant date and each year thereafter.
     Under the terms of this grant, these shares will be converted from Lucent
     shares to Agere shares on the date of the IPO. Any future adjustment will
     be consistent with adjustments generally made to restricted shares granted
     to similarly situated employees. In the event of a Company initiated
     termination other than for "cause" (as defined below) the shares will vest
     100%.

-    The Company will provide you with a cash sign-on bonus of $270,000 to
     address the calendar year 2000 annual and long-term incentive awards you
     will forfeit upon leaving your current employer. It also comprehends the
     forfeiture of your interest in other unvested long-term performance awards
     that would be payable in future years. The sign-on bonus, less applicable
     taxes, will be payable on or about March 1, 2001. This payment will not be
     made if you voluntarily resign from your position with the Company prior to
     the time it is due.

Amounts paid under this hiring incentive section are not considered earnings
for employee benefit purposes.

SEVERANCE BENEFIT: In the event of any Company initiated termination other than
for "cause" (as defined below) under the Company's officer severance policy you
will be entitled to a severance payment equal to two times your base salary and
target incentive in effect at the time of termination.

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Mark T. Greenquist
December 15, 2000
Page 3


In addition, if the spin-off does not occur by March 1, 2002, and the Company
does not offer you continued employment as an officer at least at the same
salary and target incentive level, you would be eligible to receive the
severance benefit described above.

Such severance payment as described above, will be conditioned upon you signing
a release and agreement not to sue the Company or any affiliate of the Company.
The form of this release and agreement will be the same as the standard release
then in use for Company officers.

For purposes of this employment letter, "cause" shall be defined as follows: (1)
your conviction (including a plea of guilty or nolo contendere) of a felony or
any crime of theft, dishonesty or moral turpitude; or (2) gross omission or
gross dereliction of any statutory or common law duty of loyalty to the Company,
or (3) violation of Lucent's Business Guideposts - the Company's Code of Conduct
(or successor document).

SPECIAL PAYMENT: In order to address the unlikely possibility that the spin-off
does not occur prior to March 1, 2002, which could diminish the scope of your
responsibilities as EVP & CFO, you would be eligible to receive a cash payment
of $680,000 (less applicable taxes) on March 1, 2002, if, by that time, you
remain employed with Lucent Technologies.

OFFICER AND GENERAL EMPLOYEE BENEFITS PLANS: ATTACHMENT A is a summary of
benefits available to you under the current officer and general employee benefit
plans. A Benefits representative will personally meet with you to review these
benefit plans.

RELOCATION PLAN: You will be eligible for the standard relocation package.
However, before we can commit to specifics we will need more details concerning
your current situation in Switzerland.

CONFIDENTIALITY OF AGREEMENT: It is agreed and understood that you will not talk
about, write about or otherwise disclose the terms or existence of this
employment letter or any fact concerning its negotiation or implementation. You
may, however, discuss the contents of this letter with your family, legal and/or
financial counselor.

CONTINGENCY OF OFFER: This offer of employment is contingent upon the successful
completion of reference checks and upon your meeting our medical requirements.
Our medical review includes an evaluation of your Pre-placement Health
Questionnaire, a mandatory drug screen, and a physical examination. A positive
drug screen result will automatically mean rescission of this employment offer.

This letter supersedes and completely replaces any prior oral or written
communication about your employment with Agere. This letter is not an employment
contract and should not be construed or interpreted as containing any guarantee
of continued employment. The employment relationship at the Company is by mutual
consent ("Employment-At-Will"). This means that managers have the right to
terminate their employment at any time and for any
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Mark T. Greenquist
December 15, 2000
Page 4



reason. Likewise, the Company reserves the right to discontinue your employment
with or without cause at any time for any reason.

BENEFIT PLAN TERMS: The incentive plans as well as the employee and officer
benefit plans, programs and practices as briefly outlined in this letter,
reflect their current provisions. Payments and benefits under these plans and
programs, as well as other payments referred to in this letter, are subject to
IRS rules and regulations with respect to withholding, reporting, and taxation,
and will not be grossed-up unless specifically stated. The Company reserves the
right to discontinue or modify any compensation, incentive, benefit, perquisite
plan, program or practice. Moreover, the very brief summaries contained herein
are subject to the terms of such plans, programs and practices. If there is any
difference between these summaries and the formal plan documents, the
provisions of the plan documents will prevail.

For purposes of the officer and employee benefits plans, the definition of
compensation is as stated in the plans. Currently, pensions are based on base
salary and actual short term incentive awards. Other pay-related benefits are
based either on base salary or base salary plus the target award under the
short term plan. All other compensation and payments reflected in this offer
are not included in the calculation of any employee or officer benefits (except
for the Deferred Compensation Plan which currently permits the deferral of base
salary and certain incentives).

NON-COMPETITION: The Supplemental Pension Plan, the Deferred Compensation Plan
and the Executive Life Insurance Plan are subject to non-compensation
constraints.

PROPRIETARY INFORMATION AND EMPLOYMENT LIMITATIONS: By acceptance of this offer,
you agree that (1) no trade secret or proprietary information belonging to your
previous employer will be disclosed or used by you at the Company, and that no
such information, whether in the form of documents, memoranda, software,
drawings, etc. will be retained by you or brought with you to the Company, and
(2) you have brought to the Company's attention and provided it with a copy of
any agreement which may impact your future employment at the Company, including
non-disclosure, non-competition, invention assignment agreements or agreements
containing future work restrictions, and that you certify that you have no
restrictions under any agreement of this type that would impact this work
assignment at Agere.

If you agree with the foregoing, and affirm that there are no agreements or
other impediments that would prevent you from providing exclusive service to the
Company, please sign this letter in the space provided below and mail the
original executed copy to me at your earliest convenience.

Mark, we would be very pleased to have you join the team and are excited about
the opportunity we would have to achieve breakthrough results together at Agere.
As a Company, we have never been better positioned to take full advantage of the
opportunities for growth and success in our marketplace. I look forward to
having you join us. If you have any questions, please do not hesitate to call
me, Pam Kimmet, Vice President, Compensation and Benefits on (908) 582-8557 or
Pat Matthews of our Executive Compensation and Benefits group on (908) 582-6468.



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Mark T. Greenquist
December 15, 2000
Page 5



I look forward to your response.



Sincerely,


/s/ John T. Dickson
John T. Dickson
President and CEO (designate)
Agere Systems Inc.



/s/ Mark T. Greenquist             15.12.00
Acknowledged and Agreed to:        Date
Mark T. Greenquist



Attachment