1
                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                    FORM 8-K

                                 CURRENT REPORT
                     Pursuant to Section 13 or 15(d) of the
                         Securities Exchange Act of 1934



                               September 13, 1998
                Date of Report (Date of earliest event reported)



                                CIENA Corporation
             (Exact name of registrant as specified in its charter)



          Delaware                      0-21969                   23-2725311
(State or other jurisdiction          (Commission               (IRS Employer
     of incorporation)                 File No.)             Identification No.)



                 1201 Winterson Road, Linthicum, Maryland 21090
               (Address of principal executive offices) (Zip Code)



               Registrant's telephone number, including area code:
                                 (410) 865-8500



                                 Not applicable
          (Former name or former address, if changed since last report)


                            Exhibit Index on Page 4
   2
Item 5. Other Events.

            CIENA Corporation and Tellabs, Inc. announced on September 14,
1998 that they had agreed to terminate the Agreement and Plan of Merger dated as
of June 2, 1998, as amended by the First Amendment to Agreement and Plan of
Merger dated as of August 27, 1998 (as so amended, the "Merger Agreement"). In
accordance with the terms of the Termination Agreement, a copy of which is
attached hereto as Exhibit 99.1 and incorporated by reference herein, all
related agreements including the Stock Option Agreement are also terminated.
Certain provisions relating to confidentiality survive the termination of the
Merger Agreement. Under the terms of the Termination Agreement, no termination
fees are payable by either party.

       Also, in connection with the termination of the Merger Agreement, CIENA
has amended its Shareholder Rights Agreement dated December 29, 1997, as amended
on June 2, 1998, to provide that the amendments made on June 2, 1998 in
contemplation of the Merger are rescinded. The Second Amendment to the Rights
Agreement is attached hereto as Exhibit 99.2 and incorporated by reference
herein.


Item 7. Financial Statements, Pro Forma Financial Information and Exhibits.

            99.1 Termination Agreement, dated September 13, 1998.

            99.2 Second Amendment to Rights Agreement, dated September 13, 1998.




                                      -2-
   3
                                   SIGNATURES


                Pursuant to the requirements of the Securities Exchange Act of
1934, as amended, the Registrant has duly caused this Report to be signed on its
behalf by the undersigned thereunto duly authorized.


                                   CIENA Corporation




Date:  September 14, 1998               By: /s/ G. Eric Georgatos
                                            -----------------------------------
                                                G. Eric Georgatos
                                                Vice-President, General Counsel
                                                  and Secretary




                                      -3-
   4
                                  EXHIBIT INDEX



Exhibit No. Description - ----------- ----------- 99.1 Termination Agreement, dated September 13, 1998. 99.2 Second Amendment to Rights Agreement, dated September 13, 1998.
-4-
   1
                                  EXHIBIT 99.1

                              TERMINATION AGREEMENT


   2
                              TERMINATION AGREEMENT

                  This Termination Agreement (this "Termination Agreement") is
made as of this 13th day of September, 1998, among Tellabs, Inc., a Delaware
corporation ("Parent") and CIENA Corporation, a Delaware corporation (the
"Company").

                  WHEREAS, Parent, White Oak Merger Corp., a Delaware
corporation and a direct wholly owned subsidiary of Parent ("Sub") and Company
are parties to that certain Agreement and Plan of Merger dated as of June 2,
1998, as amended by the First Amendment to Agreement and Plan of Merger dated as
of August 27, 1998 (as so amended, the "Merger Agreement"); and

                  WHEREAS, the parties desire to terminate the Merger Agreement
by mutual consent as provided by Section 7.1 (a) of the Merger Agreement.

                  NOW, THEREFORE, in consideration of the premises and
agreements contained herein and other good and valuable consideration, the
receipt and sufficiency of which the parties hereby acknowledge, the parties
hereto agree as follows:

                           1. CAPITALIZED TERMS. Except as otherwise defined or
modified herein, all capitalized terms used in this Termination Agreement shall
have the meanings set forth in the Merger Agreement.

                           2. TERMINATION OF AGREEMENT. Effective immediately
upon execution of this Termination Agreement, the Merger Agreement is hereby
terminated pursuant to Section 7.1 (a) thereof, and the Stock Option Agreement
is hereby terminated pursuant to Section 19 thereof. All covenants,
undertakings, restrictions and limitations contained in all Company Affiliate
Letters, Parent Affiliate Letters, the Stockholders Agreement dated as of August
27, 1998 between the Company and Michael Birck and the Stockholder Agreements
executed in connection with the Merger Agreement (collectively with the Merger
Agreement and the Stock Option Agreement, the "Transaction Agreements") are also
terminated and waived and shall be of no further force and effect.

                           3. SURVIVAL OF CONFIDENTIALITY AGREEMENT.
Notwithstanding any provisions of the Merger Agreement to the contrary, the
provisions of Sections 2.1, 2.4, 2.7 and 2.8 of the Confidentiality Agreement
shall survive the termination of the Merger Agreement, and each party will use
commercially reasonable efforts to promptly return all Evaluation Material (as
defined in the Confidentiality Agreement) relating to the other party to the
other party or destroy the same, as requested by the other party, and will
otherwise cooperate with the other party in taking all reasonable steps
necessary to carry out an orderly termination of actions heretofore taken to
carry out the transactions contemplated by the Merger Agreement, provided,
however, that if the Receiving 


                                      -1-
   3
Company (as defined in the Confidentiality Agreement) reasonably determines that
because of pending or threatened litigation or proceedings the return or
destruction of any such materials would not be appropriate, in lieu of such
return or destruction the Receiving Company may turn over any such materials to
its outside legal counsel (who shall maintain the confidentiality thereof, use
such materials only as reasonably necessary in connection with such legal
actions or proceedings and shall promptly return or destroy such materials when
the same are no longer reasonably necessary for use in such legal action or
proceedings).

                           4. EXPENSES. Except as otherwise provided in this
Termination Agreement, all costs and expenses incurred in connection with or
relating to this Termination Agreement, the Transaction Agreements or the
transactions contemplated hereby and thereby, including, without limitation, the
fees and disbursements of counsel, financial advisors and accountants, shall be
paid by the party incurring such costs and expenses; provided, that all printing
expenses and all filing fees incurred by the parties prior to the date hereof in
connection with the Merger Agreement (including, without limitation, filing fees
under the Securities Act, the Exchange Act and the HSR Act) shall be divided
equally between Parent and the Company. Accordingly, all charges of Bowne & Co.
in connection with printing and distributing the Registration Statement and the
Joint Proxy Statement shall be borne 50% by Parent and 50% by the Company.

                           5. RELEASE AND WAIVER. Each of the parties hereto,
for itself and its subsidiaries, predecessors, successors and assigns, and for
each of its and their respective directors, officers, employees, agents and
attorneys acting as such (collectively, the "Releasing Persons"), does hereby
forever and unconditionally release, acquit and discharge each of the other
parties hereto, and each of their respective parents, subsidiaries,
stockholders, directors, officers, employees, agents, attorneys and consultants,
and the predecessors, successors and assigns of each of them (collectively, the
"Released Persons"), with all Released Persons who are natural persons being so
released, acquitted and discharged in both their individual as well as their
official capacities, from any and all claims, controversies, covenants,
representations, warranties, demands, promises, contracts, agreements, causes of
action, suits, liabilities, obligations, debts or other responsibility of
whatever kind or nature, whether known or unknown, whether in law or in equity,
which the Releasing Persons ever had, now have or may have against any Released
Person for any matter, thing, event, action or omission which in any way,
directly or indirectly, relates to or arises out of or is connected to the
Transaction Agreements, any of the transactions contemplated thereby, including,
without limitation by reason of or in connection with the termination of the
Transaction Agreements, or any other acts, facts, omissions, transactions,
occurrences or other subject matters relating thereto, arising therefrom or in
connection therewith; provided, however, that nothing contained herein shall
release any obligation under this Termination Agreement or claim to enforce it.



                                      -2-
   4
                           6. AMENDMENTS. This Agreement can be modified or
amended only by a writing signed by the parties hereto.

                           7. GOVERNING LAW. This Agreement shall be governed by
and construed in accordance with the laws of the State of Delaware, regardless
of the laws that might otherwise govern under applicable principles of conflicts
of laws thereof.

                           8. ENFORCEMENT. The parties hereto agree that
irreparable damage would occur in the event that any provisions of Section 3 of
this Termination Agreement were not performed in accordance with their specific
wording or were otherwise breached. It is accordingly agreed that the parties
hereto shall be entitled to an injunction or injunctions to prevent breaches of
Section 3 of this Termination Agreement and to enforce specifically the terms
and provisions of such Section 3 in any court of the United States or any state
having jurisdiction, such remedy being in addition to any other remedy to which
any party is entitled at law or in equity.

                           9. DISCLOSURE. Promptly following the execution
hereof, Parent and the Company shall issue the press releases in the forms
attached hereto as Exhibits A and B, respectively, or as otherwise agreed
between the parties prior to release.

                           10. REPRESENTATIONS AND WARRANTIES. Each of the
parties hereto represents and warrants to the other that (a) it has all
requisite power and authority to enter into this Termination Agreement and (b)
this Termination Agreement constitutes the legal, valid and binding obligation
of such party and (assuming that this Termination Agreement is the valid,
binding and enforceable obligation of the other party) is enforceable against it
in accordance with its terms.

                           11. EXECUTION IN COUNTERPARTS. To facilitate
execution, this Agreement may be executed in as many counterparts as may be
required; and it shall not be necessary that the signatures of, or on behalf of,
each party, or that the signatures of all persons required to bind any party,
appear on each counterpart; but it shall be sufficient that the signature of, or
on behalf of, each party, or that the signatures of the persons required to bind
any party, appear on one or more of the counterparts. All counterparts shall
collectively constitute a single agreement. It shall not be necessary in making
proof of this Agreement to produce or account for more than a number of
counterparts containing the respective signatures of, or on behalf of, all of
the parties hereto.




                                      -3-
   5
                           12. ENTIRE AGREEMENT. Except as set forth in Section
3 hereof with respect to certain provisions of the Confidentiality Agreement,
this Agreement constitutes the entire agreement between the parties with respect
to the subject matter hereof and supersedes all prior agreements and
understandings between the parties with respect thereto; including without
limitation, Section 7.2 of the Merger Agreement, the other provisions of the
Merger Agreement, all other Transaction Agreements and the Confidentiality
Agreement. Except for the provisions of Section 5 hereof, this Termination
Agreement is not intended to confer upon any person other than the parties
hereto any rights or remedies hereunder.

                  IN WITNESS WHEREOF, the undersigned have executed this
Termination Agreement as of the date first above written.

ATTEST/WITNESS:                    TELLABS, INC.


/s/                                By:  /s/ Michael J. Birck              (SEAL)
- ------------------------------          ---------------------------------
                                        Michael J. Birck
                                        President and Chief Executive Officer


                                   CIENA CORPORATION

 /s/                               By:  /s/ Patrick H. Nettles            (SEAL)
- ------------------------------          ---------------------------------
                                        Patrick H. Nettles
                                        President and Chief Executive Officer



                                   ACKNOWLEDGED AND AGREED:

                                   WHITE OAK MERGER CORP.


 /s/                               By:  /s/ Michael J. Birck              (SEAL)
- ------------------------------          ---------------------------------
                                        Michael J. Birck
                                        President and Chief Executive Officer


                                      -4-
   1
                                  EXHIBIT 99.2
                      SECOND AMENDMENT TO RIGHTS AGREEMENT




   2
                  SECOND AMENDMENT TO RIGHTS AGREEMENT, dated as of September
13, 1998 (the "Amendment"), between CIENA Corporation, a Delaware corporation
(the "Company"), and BankBoston N.A.(the "Rights Agent").

                  WHEREAS, the Company and the Rights Agent are parties to the
Rights Agreement dated as of December 29, 1997, as amended by the First
Amendment to Rights Agreement dated June 2, 1998 (the "Agreement");

                  WHEREAS, the Company has delivered to the Rights Agent an
appropriate certificate pursuant to Section 27 of the Agreement; and

                  WHEREAS, in accordance with Section 27 of the Agreement, the
Company and the Rights Agent desire to amend the Agreement as set forth below.

                  NOW, THEREFORE, in consideration of the premises and the
mutual agreements herein set forth, the parties hereby agree as follows:

                  SECTION 1. AMENDMENTS TO SECTION 1. (a) Section 1(c) of the
Agreement relating to the definitions of "Beneficial Owner" and "beneficially
own" is amended by deleting the following:

                  "Notwithstanding anything contained in this Agreement to the
contrary, neither Tellabs nor White Oak, nor any of their Affiliates or
Associates, shall be deemed to be the Beneficial Owner of, nor to beneficially
own, any of the Common Stock of the Company solely by virtue of the approval,
execution or delivery of the Merger Agreement, the Stock Option Agreement or the
Stockholder Agreements, the acquisition of Common Stock pursuant to the terms of
the Stock Option Agreement or the consummation of the Merger and the other
transactions contemplated by the Merger Agreement, the Stock Option Agreement
and the Stockholder Agreements."

                  (b) Section 1 of the Agreement is amended by deleting the
following at the end thereof:

                  "(dd) The following additional terms have the meanings
indicated: "Merger" shall mean the merger of White Oak with and into the Company
in accordance with the General Corporation Law of the State of Delaware upon the
terms and subject to the conditions set forth in the Merger Agreement. "Merger
Agreement" shall mean the Agreement and Plan of Merger, dated as of June 2,
1998, by and among Tellabs, White Oak and the Company (as such agreement may be
amended from time to time). "Stockholder Agreements" shall mean the Stockholder
Agreements, dated as of June 2, 1998, by and between Tellabs and certain
stockholders of the Company (as such agreements may be amended from time to
time). "Stock Option Agreement" shall mean the Stock Option Agreement, dated as
of June 2, 1998, by and between Tellabs and the Company (as such 


                                      -1-
   3
agreement may be amended from time to time). "Tellabs" shall mean Tellabs, Inc.,
a Delaware corporation. "White Oak" shall mean White Oak Merger Corp., a
Delaware corporation, and wholly-owned subsidiary of Tellabs."

                  SECTION 2. EXPIRATION DATE. Section 7(a) of the Agreement is
hereby amended (a) by replacing the comma that appears immediately prior to the
symbol "(iv)" with an ", or"; (b) by deleting the following to the end of the
Section 7(a): ", or (v) the time immediately prior to the Effective Time (as
defined in the Merger Agreement), whereupon the Rights shall expire (the
earliest of (i), (ii), (iii), (iv) and (v) being herein referred to as the
"Expiration Date")." ;and (c) by inserting in place thereof the following
parenthetical "(the earliest of (i), (ii), (iii) and (iv) being herein referred
to as the "Expiration Date")."

                  SECTION 3. DELETE SECTION 35. Section 35 is hereby deleted in
its entirely.

                  SECTION 4. SEVERABILITY. If any term, provision, covenant or
restriction of this Amendment is held by a court of competent jurisdiction or
other authority to be invalid, void or unenforceable, the remainder of the
terms, provisions, covenants and restrictions of this Amendment shall remain in
full force and effect and shall in no way be affected, impaired or invalidated.

                  SECTION 5. GOVERNING LAW. This Amendment shall be deemed to be
a contract made under the laws of the State of Delaware and for all purposes
shall be governed by and construed in accordance with the laws of such state.

                  SECTION 6. COUNTERPARTS. This Amendment may be executed in any
number of counterparts and each of such counterparts shall for all purposes be
deemed to be an original, and all such counterparts shall together constitute
but one and the same instrument.

                  SECTION 7. EFFECT OF AMENDMENT. Except as expressly modified
herein, the Agreement shall remain in full force and effect.



                                      -2-
   4
                  IN WITNESS WHEREOF, the parties hereto have caused this
Amendment to be duly executed and their respective corporate seals to be
hereunto affixed and attested, all as of the day and year first above written.


Attest:                                    CIENA CORPORATION
/s/ G. Eric Georgatos                      By: /s/ Patrick H. Nettles
G. Eric Georgatos                          Patrick H. Nettles
Vice President, General                    President and Chief Executive
Counsel and Secretary                      Officer


Attest: BANKBOSTON, N.A.

/s/ Linda Adams
By: /s/ Margaret Prentice
Name: Margaret Prentice
Title: Administrative Manager




                                      -3-