POWER OF ATTORNEY

I, Stephanie Pace Marshall, of 1415 West Diehl Road, Naperville, Illinois 60563,
hereby appoint each of James Sheehan of 1415 West Diehl Road, Naperville,
Illinois 60563, Paul Liebenson of 1415 West Diehl Road, Naperville, Illinois
60563 and Scott Morgan of 1465 N. McDowell Blvd., Petaluma, California 94954, as
attorney-in-fact to act for me and in my name for the purpose of completing,
signing and filing, in my name and on my behalf, any of the following forms
pursuant to the terms of Securities Exchange Act of 1934 and the Securities Act
of 1933:

        Form 3 - Initial Statement of Beneficial Ownership of Securities

        Form 4 - Statement of Changes of Beneficial Ownership of Securities

        Form 5 - Annual Statement of Beneficial Ownership of Securities

        Form 144 - Notice of Proposed Sale of Securities

This power shall become effective on January 1, 2006, and shall continue in
effect until terminated in writing by me or until either of my attorneys-in-fact
shall die, become legally disabled, terminate their employment with Tellabs,
Inc. or its subsidiaries for any reason, resign or refuse to act (only as
applies to such person, this power shall otherwise remain in force for the
remaining attorneys-in-fact).

I am fully informed as to all the contents of this form and understand the full
import of this grant of powers to either of my attorneys-in-fact.

This Power of Attorney shall supersede any previously granted power related to
the subject matter herein.

/s/ Stephanie Pace Marshall, PhD
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Stephanie Pace Marshall, PhD

State of Illinois       )
                        ) SS
County of Kane          )

NOTARY

The undersigned, a notary public in and for the above county and state, this 9th
day of February, 2006, certifies that Stephanie Pace Marshall, PhD, known to me
to be the same person whose name is subscribed to the foregoing Power of
Attorney, appeared before me in person and acknowledged signing and delivering
said document as his/her free and voluntary act, for the uses and purposes
therein set forth.

/s/ Paula Leifheit
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Notary Public