POWER OF ATTORNEY
The undersigned hereby constitutes and appoints each of David M.
Rothenstein, Erik J. Lichter and Michelle Rankin, or their respective
assignees, each signing singly, the undersigned's true and lawful attorney-in-
fact to:
(1) execute for and on behalf of the undersigned Form ID, Forms 3, 4 and
5, and all amendments thereto in accordance with Section 16(a) of the
Securities and Exchange Act of 1934, as amended, and the rules
thereunder;
(2) do and perform any and all acts for and on behalf of the undersigned
which may be necessary or desirable to complete and execute any such
Form ID, Form 3, 4 or 5, or any amendment or amendments thereto and
file such form with the United States Securities and Exchange
Commission, the New York Stock Exchange, the Nasdaq Stock Market and
any other authority; and
(3) take any other action of any type whatsoever in connection with the
foregoing which, in the opinion of such attorney-in-fact, may be of
benefit to, in the best interest of, or legally required by, the
undersigned, it being understood that the documents executed by such
attorney-in-fact on behalf of the undersigned pursuant to this Power
of Attorney shall be in such form and shall contain such terms as
such attorney-in-fact may approve in such attorney-in-fact's
discretion.
The undersigned hereby grants to each such attorney-in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney-in-fact, or such
attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be
done by virtue of this power of attorney and the rights and powers herein
granted. The undersigned acknowledges that the foregoing attorneys-in-fact, in
serving in such capacity at the request of the undersigned, are not assuming any
of the undersigned's responsibilities to comply with Section 16 of the
Securities Exchange Act of 1934, as amended. This Power of Attorney can only be
revoked by delivering a signed, original "Revocation of Power of Attorney" to
the attorney-in-fact and shall remain in full force and effect until such
revocation is delivered.
IN WITHNESS WHEREOF, the undersigned has caused this Power of Attorney to
be executed as of this 16 day of October, 2018.
/s/ Joanne B. Olsen
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Joanne B. Olsen
