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  As Of               Filer                 Filing     As/For/On Docs:Pgs              Issuer               Agent

 3/24/04  Ciena Corp                        S-4                    2:160                                    950133

Document/Exhibit                   Description                      Pages   Size 

 1: S-4         Form S-4 for Ciena Corporation                      HTML  1,300K 
 2: EX-23.1     Consent of Independent Accountants                  HTML      5K 

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FORM S-4

REGISTRATION STATEMENT

CIENA Corporation

1201 Winterson Road

Russell B. Stevenson, Jr.

Copies to:

     Approximate date of commencement of proposed sale to the public: As soon as practicable after this Registration Statement becomes effective and all other conditions to the merger contemplated by the Agreement and Plan of Merger dated as of February 18, 2004, as such agreement may be amended, described in the enclosed Prospectus have been satisfied or waived.

     If the securities being registered on this Form are being offered in connection with the formation of a holding company and there is compliance with General Instruction G, check the following box. o

     If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act of 1933, please check the following box and list the Securities Act of 1933 registration statement number of the earlier effective registration statement for the same offering. o          

     If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act of 1933, check the following box and list the Securities Act of 1933 registration statement number of the earlier effective registration statement for the same offering. o          

CALCULATION OF REGISTRATION FEE

(1)	The Registration Statement covers the maximum number of shares of CIENA common stock that are expected to be issued in connection with the transactions described herein in the proposed merger of Catena Networks, Inc. with and into CIENA.
(2)	Includes corresponding rights to purchase shares of CIENA Series A Junior Participating Preferred Stock pursuant to a Rights Agreement dated as of December 29, 1997, as amended, between CIENA and Equiserve Trust, N.A. (formerly BankBoston N.A.)
(3)	Pursuant to Rule 457(f)(2), because there is currently no public trading market for Catena’s common and preferred stock, the registration fee was computed on the basis of 1/3 of the par value of the shares of common and preferred stock of Catena computed as of March 23, 2004. The par value equaled $98,272.11 in the aggregate.

        The registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, or until the Registration Statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

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The information in this proxy statement/ prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This proxy statement/prospectus is not an offer to sell these securities and we are not soliciting offers to buy these securities in any state where the offer or sale is not permitted.

Subject to completion, dated March 24, 2004.

Dear Stockholders:

     After careful consideration, the boards of directors of Catena Networks, Inc. and CIENA Corporation have approved the merger of Catena with CIENA. I am pleased to provide to you the enclosed proxy statement/ prospectus relating to a special meeting of the stockholders of Catena to be held on                 , 2004, at 8:00 a.m., local time, at the offices of Catena at 307 Legget Drive, Kanata, Ontario, Canada. At the special meeting, you will be asked to vote, in person or by proxy, on the proposed merger of Catena with CIENA and other related matters described below. All of these matters are described in more detail in the notice of special meeting immediately following this letter and the enclosed proxy statement/ prospectus.

     The first item we are asking you to approve is the merger agreement itself. If the merger is consummated, each outstanding share of capital stock of Catena would be converted into the right to receive shares of CIENA common stock and each outstanding warrant and option to acquire Catena capital stock would become exercisable for shares of CIENA common stock. In the merger, CIENA would issue up to a total of approximately 75.9 million shares of CIENA common stock. These shares would be allocated between Catena’s outstanding shares of capital stock and outstanding warrants and options to purchase Catena capital stock as described in the enclosed proxy statement/ prospectus. CIENA common stock is traded on the Nasdaq National Market under the symbol “CIEN.” The closing price for CIENA common stock reported on the Nasdaq National Market on March 22, 2004 was $4.77 per share. Following the merger, based on 475,254,814 outstanding shares of CIENA common stock as of March 17, 2004, and assuming all of the Catena stock options and warrants have been exercised, Catena stockholders would own approximately 13.2% of the combined company and CIENA stockholders would own approximately 86.8% of the combined company (including shares that may be issued to former stockholders of Internet Photonics, Inc., which CIENA is proposing to acquire in a separate merger agreement announced by CIENA on February 19, 2004).

     We are also asking you to approve a proposed amendment and restatement of our certificate of incorporation. As described in the enclosed proxy statement/ prospectus, the distribution of merger proceeds under the merger agreement is different from the distribution that would be obtained if the merger proceeds were allocated in accordance with the liquidation provisions of our certificate of incorporation. In order to effect the distribution of merger proceeds as described in our merger agreement with CIENA and to complete the merger, our certificate of incorporation must be amended to provide that the merger with CIENA is not an “Acquisition” or “Asset Transfer” that would trigger the application of these liquidation provisions. The amended and restated certificate of incorporation would be filed and become effective immediately prior to the merger.

     In addition, we are asking you to approve certain benefits provided to our U.S. executive officers. In connection with the merger, CIENA and Catena agreed to cause all Catena options held by each of our officers to vest (i.e., become exercisable) in full if his or her employment is terminated by CIENA or Catena without cause, or if the officer terminates his or her employment for good reason, at any time. In the event of such termination, an officer also would receive a severance payment equal to six months of his or her base salary and continuation or subsidization of his or her medical benefits for the six months following termination of employment. If granted to officers that are U.S. taxpayers, such acceleration of vesting and severance benefits may result in the imposition of an excise tax on such officers and a denial of a U.S. federal income tax deduction for Catena or CIENA, as Catena’s successor, with respect to such payments unless such payments are approved by the Catena stockholders. We are seeking your approval for such acceleration of vesting and severance benefits so that our U.S. executive officers may receive the same severance payments as our other executive officers.

     Further, we are asking that you specifically grant our board of directors the discretionary authority to postpone or adjourn the special meeting of stockholders if needed to obtain the necessary votes to approve the matters described above.

     Our board of directors has carefully reviewed and considered the terms of the merger and the merger agreement, including the distribution of proceeds and officer benefits provisions described above, and has concluded that the terms are fair to, and in the best interests of, Catena and its stockholders. Catena’s board of directors recommends that you vote “FOR” approval and adoption of the merger agreement, “FOR” approval and adoption of the amendment and restatement of Catena’s certificate of incorporation, “FOR” approval of the executive officer benefits and “FOR” the grant of discretionary authority to postpone or adjourn the meeting.

     Your vote is very important. Whether or not you plan to attend the special meeting, please take the time to vote by promptly completing and mailing the enclosed proxy card in the postage-paid envelope provided. Before you vote, please review the enclosed proxy statement/ prospectus and in particular review the matters referred to under “Risk Factors” starting on page 10.

     Finally, this letter, together with the enclosed proxy statement/prospectus, constitutes the notice of actions taken by our stockholders that we are required to provide under Section 228(e) of the Delaware General Corporation Law to stockholders that did not consent to such actions. First, we recently amended our certificate of incorporation (i) to prohibit holders of our preferred stock from voluntarily converting their shares into shares of our voting common stock prior to July 31, 2004 and (ii) to prohibit the automatic conversion of various series of our preferred stock into voting common stock prior to July 31, 2004, based on group elections by the holders of the various series of preferred stock. The amendment was approved by our board of directors on February 17, 2004, and by our stockholders by written consent effective February 17, 2004. Second, by written consent effective March 4, 2004, our stockholders granted our board of directors discretionary authority to declare, in total, a cash dividend to holders of our preferred stock of up to $10 million.

	On Behalf of the Board of Directors of Catena,
	/s/Gudmundur Hjartarson
	Gudmundur (“Jim”) Hjartarson
	President and Chief Executive Officer

Prospectus dated [                  ], 2004

Neither the Securities and Exchange Commission nor any state securities regulator has approved or disapproved of these securities or passed upon the adequacy or accuracy of this proxy statement/ prospectus. Any representation to the contrary is a criminal offense.

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CATENA NETWORKS, INC.

NOTICE OF SPECIAL MEETING OF STOCKHOLDERS

TO BE HELD ON [                               ], 2004

To the stockholders of Catena:

      A special meeting of the stockholders of Catena Networks, Inc., a Delaware corporation, will be held at the offices of Catena Networks, Inc., 307 Legget Drive, Kanata, Ontario, Canada on [                    ], 2004 at 8:00 a.m., local time, for the following purposes:

      1. To approve and adopt the Agreement and Plan of Merger, dated as of February 18, 2004, as amended, by and among CIENA Corporation, Catena Networks, Inc. and certain officers of Catena pursuant to which Catena will be merged with and into CIENA, with CIENA being the surviving corporation. A copy of the Agreement and Plan of Merger, as amended (the “merger agreement”), is attached as Annex A to the proxy statement/ prospectus accompanying this notice;

      2. To approve and adopt the amendment and restatement of Catena’s certificate of incorporation to provide that the merger of Catena into CIENA is not an “Acquisition” or “Asset Transfer” of Catena that would be treated as a “liquidation” of Catena as defined therein;

      3. To approve the payments to [                               ] (the “disqualified individuals”) of amounts that would otherwise result in “parachute payments” under Section 280G of the Internal Revenue Code of 1986 (the “Tax Code”);

      4. To grant discretionary authority to the Catena board of directors to adjourn or postpone the Catena special meeting to solicit additional votes to approve the matters considered at the special meeting, if necessary; and

      5. To consider and act upon any other matter that may properly come before the special meeting.

      This proxy statement/ prospectus and the accompanying proxy card are being furnished to the stockholders of Catena in connection with the solicitation of proxies by Catena’s board of directors for use at the special meeting of stockholders.

      Catena’s board of directors has approved the merger agreement and the amendment and restatement of Catena’s certificate of incorporation and unanimously recommends that you vote “FOR” approval and adoption of the merger agreement, “FOR” the amendment and restatement of Catena’s certificate of incorporation, “FOR” the payments that would otherwise result in “parachute payments” to “disqualified individuals” and “FOR” the grant of discretionary authority to adjourn the special meeting. The proposals are described in more detail in the accompanying proxy statement/ prospectus, which you should read in its entirety before voting.

      The board of directors has fixed the close of business on [                                                            ], 2004 as the record date for determining the stockholders entitled to receive this notice, and to vote their shares at the special meeting or any adjournment or postponement of the special meeting. Only holders of record of voting common stock and series A, series A-1, series AA, series AA-1, series B, series BB, series C, series CC, series D and series DD preferred stock (the “voting preferred stock”) will be entitled to vote at the special meeting and any adjournment or postponement of the special meeting. Holders of non-voting common stock and series B-1, series BB-1, series C-1, series CC-1, series D-1 and series DD-1 preferred stock will not be entitled to vote at the special meeting. Holders of all classes and series of Catena’s common stock and preferred stock are entitled to notice of the matters proposed to be voted on at the special meeting. As of the record date, there were (i) [9,371,695] shares of voting common stock outstanding, (ii) [10,100,000] shares of series A preferred stock outstanding, (iii) [440,000] shares of series A-1 preferred stock outstanding, (iv) [7,677,856] shares of series B preferred stock outstanding, (v) [7,514,978] shares of series C preferred stock outstanding, and (vi) [61,982,888] shares of series D preferred stock outstanding. As of the record date, no shares of series AA, series AA-1, series BB, series BB-1, series CC, series CC-1, series D-1, series DD or series DD-1 were issued and outstanding. A complete list of stockholders entitled to vote at the special meeting will be available for examination by

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      The board of directors has designated the two persons named on the enclosed proxy card, Gudmundur Hjartarson and Kevin Forbes, to serve as proxies in connection with the special meeting. All properly executed proxy cards will be voted (except to the extent that authority to vote has been withheld), and where a choice has been specified by the stockholder as provided in the proxy card, it will be voted in accordance with the specifications on the proxy card. If you sign and send in your proxy card and do not indicate how you want to vote, it will be voted in favor of the approval and adoption of the merger agreement, the approval and adoption of the amendment and restatement of Catena’s certificate of incorporation, the approval of the payments that would otherwise result in “parachute payments” and the other proposals. You may revoke a proxy prior to its execution by giving written notice to Kevin Forbes, the Secretary of Catena, by submission of another proxy bearing a later date, or by voting in person at the special meeting. Such notice or later dated proxy will not affect a vote on any matter taken prior to the receipt of the proxy revocation by Catena. Abstentions from voting identified as such on the proxy card are treated as present or represented for purposes of determining the presence or absence of a quorum at the special meeting. However, abstentions as to a proposal will have the same effect as votes against that proposal.

      The proxy statement/ prospectus materials are being mailed on or about [                                        ], 2004 to holders of record of Catena’s capital stock as of [                                        ], 2004. The principal executive office and mailing address of Catena is at 307 Legget Drive, Kanata, Ontario K2K 3C8.

      WHETHER OR NOT YOU PLAN TO ATTEND THE SPECIAL MEETING, PLEASE SIGN, DATE AND PROMPTLY RETURN THE ENCLOSED PROXY CARD, WHICH YOU MAY REVOKE AT ANY TIME PRIOR TO ITS USE. PROMPTLY SIGNING AND RETURNING YOUR PROXY CARD WILL HELP ENSURE THE PRESENCE OF A QUORUM FOR THE SPECIAL MEETING. A postage-paid, self-addressed envelope is enclosed for your convenience. Your shares will be voted at the special meeting in accordance with your proxy.

	By Order of the Board of Directors of Catena,
	/s/ GUDMUNDUR HJARTARSON
	Gudmundur (“Jim”) Hjartarson
	President and Chief Executive Officer

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      This proxy statement/ prospectus incorporates important business and financial information about CIENA from documents that it has filed with the Securities and Exchange Commission but that have not been included in or delivered with this proxy statement/ prospectus. For a listing of documents incorporated by reference into this proxy statement/ prospectus, please see the section entitled “Where You Can Find More Information” beginning on page 78 of this proxy statement/ prospectus.

      CIENA will provide you with copies of this information, without charge, upon written or oral request to:

CIENA Corporation

      In addition, you may obtain copies of this information by sending an e-mail to ir@ciena.com.

      In order for you to receive timely delivery of the documents in advance of the special meeting, CIENA should receive your request no later than [                                                  ], 2004.

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QUESTIONS AND ANSWERS ABOUT THE MERGER

Q:	When and where will the special meeting take place?
A:	The special meeting will be held on [                    ], 2004 at 8:00 a.m., local time, at the offices of Catena at 307 Legget Drive, Kanata, Ontario, Canada.
Q:	What do I need to do now?
A:	You should carefully read and consider the information contained in this proxy statement/ prospectus. You should then complete and sign your proxy card and return it in the enclosed return envelope as soon as possible so that your shares will be represented at Catena’s special meeting. If you sign, date and mail your proxy card without identifying how you want to vote, your proxy will be voted “FOR”the merger, “FOR” the amendment and restatement of Catena’s certificate of incorporation, “FOR” the approval of the payments that would otherwise result in “parachute payments” and “FOR” the grant of discretionary authority to adjourn the special meeting. If you do not vote, it will have the same effect as a vote “AGAINST” the proposals. You may also vote by appearing at the special meeting and voting in person.
Q:	Who must approve the merger?
A:	In addition to the approvals of the boards of directors of CIENA and Catena, which have already been obtained, the following approvals of the stockholders of Catena must be obtained:

•	holders of a majority of Catena’s common stock entitled to vote at any annual or special meeting of Catena stockholders;
•	holders of a majority of Catena’s common stock and preferred stock that are entitled to vote at any annual or special meeting of Catena stockholders, voting together as a single class on an as-converted into common stock basis; and
•	holders of a majority of Catena’s voting preferred stock, voting together as a single class on an as-converted into common stock basis, including at least three stockholders each beneficially owning at least 400,000 shares of Catena’s capital stock (on an as-converted into common stock basis), each of whom must not be an “affiliate” of Catena as such term is defined under the federal securities laws (those stockholders are referred to as “unaffiliated investors” throughout this proxy statement/ prospectus).

Q:	Who must approve the amendment and restatement of Catena’s certificate of incorporation?
A:	In addition to the approval of the board of directors of Catena, which has already been obtained, the following approvals of the stockholders of Catena must be obtained:

•	holders of a majority of Catena’s common stock entitled to vote at any annual or special meeting of Catena stockholders;
•	holders of a majority of Catena’s common stock and preferred stock that are entitled to vote at any annual or special meeting of Catena stockholders, voting together as a single class on an as-converted into common stock basis;
•	holders of a majority of Catena’s voting preferred stock, voting together as a single class on an as-converted into common stock basis, including at least three unaffiliated investors; and
•	holders of at least 70% of Catena’s series C preferred stock.

Q:	Does the merger depend upon approval of the amendment and restatement of Catena’s certificate of incorporation?
A:	Yes. Because the distribution of merger proceeds under the merger agreement is different from the distribution that would be obtained if the merger proceeds were allocated in accordance with the liquidation provisions of Catena’s existing certificate of incorporation, Catena’s stockholders must approve the amendment and restatement of Catena’s certificate of incorporation to provide that the merger will not trigger the application of these provisions.
Q:	Who must approve the benefits to disqualified individuals?
A:	Holders of more than 75% of Catena’s outstanding stock, considered on an as-converted into common stock basis, excluding

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	shares held by the disqualified individuals, must approve the payment of amounts that would otherwise result in an excise being imposed on the disqualified individuals. However, approval of the benefits to disqualified individuals is not a condition to the consummation of the merger.
Q:	Can I change my vote after I mail my signed proxy?
A:	Yes. You can change your vote at any time before your proxy is voted at the special meeting of Catena’s stockholders. You can do this in one of three ways. First, you can send a written notice stating that you would like to revoke your proxy. Second, you can complete and submit a new proxy. If you choose either of these two methods, you must submit your notice of revocation or your new proxy at the address on page 16. Third, you can attend the special meeting of stockholders and vote in person. Your attendance alone will not revoke your proxy.
Q:	Should I send in my certificates now?
A:	No, you should not send in your stock certificates with your proxy. You will receive instructions for exchanging your stock certificates if the merger is consummated.
Q:	Who can help answer my questions?
A:	If you have any questions about the merger, how to vote or revoke your proxy, or if you need additional copies of this proxy statement/ prospectus or the enclosed proxy, you should contact Kevin Forbes, Catena’s Secretary, at (613) 591-7838.

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SUMMARY

      This summary highlights selected information from this proxy statement/ prospectus. It does not contain all of the information that is important to you. You should carefully read this proxy statement/ prospectus and the other documents incorporated by reference into this proxy statement/ prospectus. See “Where You Can Find More Information” on page 78. In this proxy statement/ prospectus, “we,” “us” and “our” may refer to either CIENA or Catena, depending on the context in which they are used, and “you” and “your” refer to stockholders of Catena.

The Companies (page 60)

CIENA Corporation

CIENA is a leader in innovative networking solutions to service providers and enterprises worldwide. CIENA’s customers include long-distance carriers, local exchange carriers, Internet service providers, wireless and wholesale carriers, systems integrators, large businesses and governmental and non-profit institutions. CIENA offers network solutions that enable service providers to provision, manage and deliver economic, high-bandwidth services to their customers. On February 19, 2004, CIENA announced an agreement to acquire Internet Photonics, Inc., a private provider of carrier grade optical Ethernet transport and switching solutions. CIENA expects to issue approximately 24.1 million shares of common stock in that acquisition.

Catena Networks, Inc.

Catena’s integrated broadband access solutions enable service providers to profitably deliver voice, data and video services and smoothly migrate to packet-based networks. These solutions include the Catena CNX-5 Broadband DSL System, the Catena CN1000 Broadband Loop Carrier, and the Catena CN1000FX Fiber-to-the-X solution suite.

Vote Required for the Merger and Other Proposals (page 13)

Under Delaware law and Catena’s certificate of incorporation, the following stockholder approvals are required to approve the merger:

	•	holders of a majority of Catena’s common stock entitled to vote at any annual or special meeting of Catena stockholders;
	•	holders of a majority of Catena’s common stock and preferred stock that are entitled to vote at any annual or special meeting of Catena stockholders, voting together as a single class on an as-converted into common stock basis; and
	•	holders of a majority of Catena’s voting preferred stock, voting together as a single class on an as-converted into common stock basis, including at least three unaffiliated investors.

Under Delaware law and Catena’s certificate of incorporation, the following stockholder approvals are required to approve the amendment and restatement of Catena’s certificate of incorporation:

	•	holders of a majority of Catena’s common stock entitled to vote at any annual or special meeting of Catena stockholders;
	•	holders of a majority of Catena’s common stock and preferred stock that are entitled to vote at any annual or special meeting of Catena stockholders, voting together as a single class on an as-converted into common stock basis;
	•	holders of a majority of Catena’s voting preferred stock, voting together as a single class on an as-converted into common stock basis, including at least three unaffiliated investors; and
	•	holders of at least 70% of Catena’s series C preferred stock.

Holders of more than 75% of Catena’s outstanding stock, considered on an as-converted into common stock basis, excluding shares held by the disqualified individuals, must approve the payment of amounts that would otherwise result in an excise tax being imposed on the disqualified individuals, and the approval of the holders of a majority of Catena’s outstanding stock, considered on an as-converted into common stock basis, is required to grant the discretionary authority to Catena’s board

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There were [9,371,695] shares of Catena voting common stock and [87,715,722] shares of Catena voting preferred stock, comprised of [10,100,000] shares of Catena series A preferred stock, [440,000] shares of Catena series A-1 preferred stock, [7,677,856] shares of Catena series B preferred stock, [7,514,978] shares of Catena series C preferred stock, and [61,982,888] shares of Catena series D preferred stock, outstanding as of the record date. Each holder of Catena common stock is entitled to one vote per share and each holder of Catena preferred stock is entitled to one vote for each full share of common stock into which its shares of preferred stock would be convertible (assuming such shares are then convertible into common stock).

CIENA and the directors and officers of Catena, including stockholders affiliated with the directors and officers, entered into agreements under which such stockholders agreed to vote their shares in favor of the merger and approval of the merger agreement and in favor of the amendment and restatement of Catena’s certificate of incorporation. As of the record date, these directors, officers and other stockholders held the following numbers of Catena shares:

	•	[6,155,675] shares of voting common stock, representing approximately [66]% of Catena’s common stock entitled to vote at any annual or special meeting of Catena stockholders;
	•	[63,036,614] shares of voting common stock and voting preferred stock considered on an as-converted into common stock basis, representing approximately [57]% of Catena’s common stock and preferred stock entitled to vote at any annual or special meeting of Catena stockholders, on an as-converted into common stock basis;
	•	[56,880,939] shares of voting preferred stock considered on an as-converted into common stock basis, representing approximately [56]% of Catena’s voting preferred stock, on an as-converted basis, and [54]% of the series C preferred stock.

Grant of Options to CIENA (page 51)

Catena officers, directors and affiliates of such directors and officers, owning in the aggregate [6,155,675] shares of Catena voting common stock, representing approximately [66]% of the outstanding Catena voting common stock as of the record date, and [56,880,939] shares of Catena voting preferred stock, representing approximately [56]% of the outstanding voting preferred stock as of the record date, have granted to CIENA options to purchase their Catena shares, subject to the limitation that CIENA cannot purchase more than 45% in the aggregate of Catena’s outstanding capital stock pursuant to the exercise of such options. The options are exercisable under several circumstances, including those when Catena is required to pay CIENA the $14.5 million termination fee provided for under the merger agreement. CIENA required these stockholders to deliver the options as a condition to CIENA’s willingness to enter into the merger agreement. Although the number of shares of Catena capital stock subject to the options is not sufficient to ensure the approval of the merger with CIENA, if the options are exercised following receipt of a competing offer to purchase the capital stock of Catena, CIENA’s consent may be necessary to complete the closing of that alternative transaction.

The Merger (page 18)

The merger agreement provides that Catena will merge with and into CIENA and CIENA will be the surviving company.

The merger agreement, as amended, is included as Annex A to this proxy statement/ prospectus. It is the legal document that governs the merger.

Recommendation of Catena’s Board of Directors and Reasons for the Merger (page 24)

The Catena board of directors has determined that the merger is advisable and in the best interests of Catena and its stockholders, as well as the proposed amendment and restatement of Catena’s certificate of incorporation and the proposed approval of “parachute payments” to the disqualified individuals. The Catena board of directors recommends that Catena stockholders vote “FOR” the proposal to approve and adopt the merger agreement and each of the other proposals.

See “The Merger — Recommendation of Catena’s Board of Directors and Reasons for the Merger”

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What you will receive in the Merger (page 37)

In the merger, you will receive CIENA common stock for each share of Catena common stock or preferred stock that you own. In the case of Catena common stock, each share is exchangeable for 0.493 shares of CIENA common stock. In the case of Catena preferred stock, the number of shares of CIENA common stock exchangeable for each share of Catena preferred stock is determined by application of the formulas set forth under “Terms of the Merger Agreement and Related Transactions — Treatment of Stock, Options and Warrants.” These formulas generally provide that holders of Catena preferred stock are entitled to the number of shares of CIENA common stock that such holder would receive if the merger were an “Acquisition” or “Asset Transfer” under Catena’s current certificate of incorporation (including by conversion of preferred stock into common stock to the extent the holder would receive more shares by doing so, disregarding for this purpose the fact that the stock is not currently convertible and the fixed exchange ratio for the Catena common stock), with this number of shares adjusted upward or downward ratably among holders of Catena preferred stock, depending on the extent to which holders of Catena common stock receive more or less consideration in the merger than they would have received were the merger to be treated as an “Acquisition” or “Asset Transfer” of Catena under Catena’s current certificate of incorporation. Accordingly, the number of shares each holder of Catena preferred stock will receive in the merger will depend on the value of CIENA’s common stock at the closing of the merger. The number of shares of CIENA common stock to be received for each share of Catena preferred stock also is subject to adjustment in the event that Catena’s fully-diluted outstanding capital stock changes due to option issuances, stock repurchases and similar events. In addition, the number of shares to be received by each Catena stockholder is subject to adjustment for stock splits, combinations and the like that may occur before the closing of the merger.

The following table illustrates the number of shares of CIENA common stock a holder of Catena preferred stock would be entitled to receive per share under the merger agreement at various hypothetical average closing prices of CIENA’s common stock calculated in accordance with Catena’s existing certificate of incorporation (“illustrative average closing prices”) assuming the total number of shares of Catena capital stock outstanding on a fully-diluted basis on the day the merger is completed is [130,205,604], which was the number of shares of capital stock outstanding on a fully-diluted basis on the record date. “Fully-diluted basis” means that all outstanding options and warrants are exercised and that all outstanding preferred stock is converted into common stock based on the then-effective conversion rates of the preferred stock. Under Catena’s existing certificate of incorporation the value of each share of CIENA common stock issuable to Catena stockholders in the merger equals the average closing price of one share of CIENA’s common stock over the 30 days ending three days prior to the closing of the merger.

You will receive cash for any fractional share of CIENA common stock that you would otherwise receive in the merger.

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Following the merger, based on 475,254,814 outstanding shares of CIENA common stock as of March 17, 2004, and assuming all of Catena’s stock options and warrants have been exercised, Catena stockholders would own approximately 13.2% of the combined company and CIENA stockholders would own approximately 86.8% of the combined company (including shares that may be issued to former stockholders of Internet Photonics, Inc., which CIENA is proposing to acquire in a separate merger agreement announced by CIENA on February 19, 2004).

Please do not send your stock certificates at this time.

Treatment of Options and Warrants (page 37)

CIENA will assume each option or warrant to acquire Catena common stock and preferred stock granted under Catena’s stock plans or otherwise issued by Catena and that is outstanding and unexercised immediately prior to the effective time of the merger. At the effective time of the merger, CIENA will replace Catena’s options and warrants with options or warrants, respectively, to purchase CIENA common stock, in each case, adjusting the number of shares issuable upon exercise and the exercise price of such option or warrant to reflect the exchange ratio in the merger applicable to the Catena common or preferred stock underlying such Catena option or warrant. The duration and other terms of each such CIENA option or warrant, including the vesting schedule, will be the same as the prior Catena stock option or warrant.

Total Consideration CIENA Will Pay (page 37)

In the merger, CIENA would issue a total of up to approximately 75.9 million shares of CIENA common stock to be allocated between Catena’s outstanding shares of capital stock and outstanding warrants and options to purchase Catena capital stock. Based on the closing price of CIENA’s common stock on March 22, 2004, these shares would have an aggregate market value of approximately $362 million.

Appraisal Rights of Dissenting Stockholders (page 34)

If you object to the merger, Delaware law permits you to seek relief as a dissenting stockholder and have the “fair value” of your shares of Catena common stock and Catena preferred stock determined by a court and paid to you in cash.

If you are a Catena stockholder and wish to dissent, you must deliver to Catena, prior to the vote on the merger at the special meeting, a written demand for appraisal of your shares. You also must not vote in favor of the merger agreement. To not vote in favor of the merger agreement, you can either:

	•	vote “no” in person at the special meeting or by proxy;
	•	abstain from voting;
	•	fail to vote; or
	•	if you returned a duly executed proxy, revoke your proxy prior to the special meeting.

Beneficial owners of Catena common stock or Catena preferred stock whose shares are held of record by another person, such as a bank, broker or nominee, and who wish to seek appraisal, should instruct the record holder to follow the appraisal procedures of Delaware law. The relevant provisions of Delaware law are technical in nature and complex. If you wish to exercise appraisal rights and obtain appraisal of the fair value of your shares, you may wish to consult with legal counsel, because the failure to comply strictly with these provisions may result in waiver or forfeiture of your appraisal rights.

A copy of the relevant section of Delaware law governing this process is attached as Annex B to this proxy statement/ prospectus.

Indemnification and Escrow Arrangement (page 45)

If the merger occurs, all holders of Catena capital stock who have not elected the appraisal rights described above will be obligated to indemnify CIENA and its affiliates against losses due to, among other things, the breach or inaccuracy of any of Catena’s representations and warranties made in the merger agreement. This obligation is limited to 10% of the total number of shares of CIENA common stock issued in the merger to holders of outstanding Catena capital stock. An escrow arrangement will be established at closing to hold these shares. Gary Morgenthaler, who is affiliated with Morgenthaler Ventures, Catena’s largest stockholder, will serve as stockholders’ representative on behalf of all former Catena

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Consequently, in some circumstances you could be required to forfeit to CIENA some of the CIENA common stock you would otherwise receive in the merger.

CIENA has also agreed to indemnify the former Catena stockholders against losses due to, among other things, the breach or inaccuracy of CIENA’s representations and warranties contained in the merger agreement. CIENA’s obligation is limited to the value of the total number of shares CIENA is issuing in the merger as of the closing.

What is Needed to Complete the Merger (page 47)

Several conditions must be satisfied before the merger will be completed. These include:

	•	adoption of the merger agreement by the Catena stockholders as described above;
	•	approval of the amendment and restatement of Catena’s certificate of incorporation; and
	•	other customary contractual conditions set forth in the merger agreement, including a condition that CIENA’s stock price will be at a certain minimum level at the time the Catena stockholder vote is obtained.

If the law permits, CIENA or Catena may each waive conditions for the their benefit and their stockholders’ benefit and complete the merger even though one or more of these conditions has not been met. Catena’s stockholder approval cannot be waived. We cannot assure you that the conditions will be satisfied or waived or that the merger will occur.

Termination of the Merger Agreement (page 48)

CIENA and Catena may mutually agree at any time to terminate the merger agreement without completing the merger, even if the Catena stockholders have approved it. Either party (so long as it has not materially breached the merger agreement in a manner that caused the merger not to be consummated or caused the failure to obtain stockholder approval) may terminate the merger if:

	•	the merger has not been consummated by July 31, 2004; or
	•	Catena stockholders do not approve the merger.

In addition, either CIENA or Catena may terminate the merger agreement if:

	•	a court or other governmental authority of competent jurisdiction permanently enjoins the merger from occurring; or
	•	the terminating party is not in material breach of its obligations, and the other party has breached its obligations, or the representations and warranties of the other party are inaccurate, in either case such that the terminating party’s conditions to closing will not be fulfilled, if such breach or inaccuracy is not cured within ten days after notice.

Catena may terminate the merger agreement prior to obtaining stockholder approval, so long as it has not materially breached the merger agreement, if:

	•	the Catena board of directors determines to enter into an alternative transaction that it views as superior to the merger;
	•	CIENA does not match the offer made in the other transaction; and
	•	Catena pays to CIENA the $14.5 million termination fee described below.

CIENA may also terminate the merger agreement if Catena’s board of directors withdraws, modifies or amends, in any respect adverse to CIENA, its recommendation in favor of the merger and the adoption of the amendment and restatement of Catena’s certificate of incorporation or determines to pursue another transaction it considers superior.

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Amendment and Restatement of Catena’s Certificate of Incorporation (page 52)

Catena’s board of directors has determined that the CIENA stock to be issued as consideration in connection with the merger should be distributed in a manner that differs from the results that would be obtained under the existing certificate of incorporation of Catena if the merger were treated as an “Acquisition” or “Asset Transfer” resulting in the “liquidation” of Catena. Accordingly, Catena’s board of directors has approved, subject to stockholder approval, the amendment and restatement of Catena’s certificate of incorporation to exclude the merger from the application of certain provisions in Catena’s certificate of incorporation that would treat the merger as an “Acquisition” or “Asset Transfer” so that the merger consideration will be allocated as provided in the merger agreement. See “Approval of Amendment and Restatement of Catena’s Certificate of Incorporation” for a description of the effect of this amendment.

U.S. Federal Income Tax Consequences (page 30)

In the opinion of Hogan & Hartson L.L.P., counsel to CIENA, and Cooley Godward LLP, counsel to Catena, the merger will qualify as a tax-free reorganization for U.S. federal income tax purposes. As a general matter, therefore, no gain or loss will be recognized under U.S. federal income tax laws by Catena stockholders on the exchange of their Catena capital stock for CIENA common stock pursuant to the reorganization, except with respect to cash received in lieu of fractional shares and cash received for Catena shares by Catena stockholders who dissent to the merger and exercise their appraisal rights under Delaware law.

Canadian Federal Income Tax Consequences (page 33)

A Catena stockholder who is resident in Canada or is deemed to be resident in Canada (other than a holder who dissents from the merger) who receives CIENA common stock in exchange for such holder’s shares of Catena capital stock should not realize either a capital gain or a capital loss as a result of the merger.

You should consult your tax advisor for a full explanation of the tax consequences of the merger to you.

Accounting Treatment (page 30)

The merger is expected to be accounted for using the purchase method of accounting. CIENA will be deemed the acquiror for financial reporting purposes. Under the purchase method of accounting, the purchase price in the merger is allocated among the Catena assets acquired and the Catena liabilities assumed to the extent of their fair market value, with any excess purchase price being allocated to goodwill.

Governmental and Regulatory Approvals (page 30)

The Hart-Scott-Rodino Antitrust Improvements Act of 1976 as amended (the “HSR Act”) and its related rules and regulations prohibit Catena and CIENA from completing the merger until CIENA and Catena each file notifications with the Antitrust Division of the Department of Justice and the Federal Trade Commission, and the Hart-Scott-Rodino waiting period requirements have been satisfied. Even after the Hart-Scott-Rodino waiting period expires or is terminated, and even after the merger is completed, the Antitrust Division or the Federal Trade Commission could challenge the merger on antitrust grounds. In addition, before or after the merger is completed, states and private litigants could also challenge the merger on antitrust grounds. CIENA and Catena each filed Hart-Scott-Rodino notifications with the Federal Trade Commission and the Antitrust Division on February 25, 2004, and the waiting period was terminated on March 8, 2004.

Approval of Parachute Payments in Connection With the Merger (page 56)

In connection with the change in control that results from the merger of Catena into CIENA, certain U.S. executive officers of Catena could receive payments that could constitute so-called “parachute payments” under the Tax Code. For these individuals, these payments may arise as a result of the following:

	•	the value of acceleration of vesting in shares of restricted Catena common stock;

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	•	the value of acceleration of vesting in options to acquire Catena common stock; and
	•	the value of severance payments and subsidization of medical benefits to be received pursuant to the terms of severance agreements.

Under Section 280G of the Tax Code, an amount paid to certain individuals that is contingent on a change in ownership or a change in control of a corporation is a “parachute payment” if the aggregate present value of all payments made to an individual in connection with such transaction exceeds three times the disqualified individual’s “base amount.” An amount is an “excess parachute payment” to the extent the amount exceeds one times the disqualified individual’s base amount. To the extent payments are excess parachute payments, they are not deductible by the corporation and an excise tax (in addition to regular income and employment taxes) is imposed on the recipient if the recipient is a U.S. taxpayer. However, payments will not be treated as parachute payments if holders of more than 75% of the voting power of all outstanding capital stock of Catena, other than stock held by the disqualified individuals and certain related persons, approve these payments. If the payments are not approved, each disqualified individual has agreed to forego the portion of the payments that would be taxable as an excess parachute payment. You are being asked to vote to approve these payments by a separate vote from your vote on the merger. For a further discussion of the treatment of these payments and stockholder approval of these payments, see “Approval of Payments In Connection With the Merger.”

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SUMMARY SELECTED CONSOLIDATED HISTORICAL

      The information in the following summary selected consolidated financial data as of October 31, 1999, 2000, 2001, 2002 and 2003 and for the years ended October 31, 1999, 2000, 2001, 2002 and 2003 is derived from CIENA’s audited consolidated financial statements. You should read this information in conjunction with the financial statements and notes to the consolidated financial statements that are incorporated by reference into this proxy statement/ prospectus. Selected financial information as of January 31, 2004 and for the three months ended January 31, 2004 and January 31, 2003 is derived from CIENA’s unaudited consolidated financial statements, which are incorporated by reference into this proxy statement/ prospectus. See “Where You Can Find More Information” which begins on page 78. CIENA has a 52 or 53 week fiscal year, which ends on the Saturday nearest to the last day of October in each year. For purposes of financial statement presentation, each fiscal year is described as having ended on October 31. Fiscal 1999, 2000, 2002 and 2003 comprised 52 weeks and fiscal 2001 comprised 53 weeks. Historical events are not necessarily indicative of results to be expected in the future and results of interim periods are not necessarily indicative of the results of the entire year.

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RISK FACTORS

      In addition to the risks described in CIENA’s most recently filed Form 10-Q under Item 2, you should carefully consider the following risk factors relating to the merger before deciding how to vote your shares. You should also consider the other information contained in or incorporated by reference into, this proxy statement/ prospectus. See “Where You Can Find More Information” on page 78.

The value and number of shares of the CIENA common stock that Catena stockholders receive in the merger will depend on its market price at the time of the merger.

      The value of CIENA common stock that Catena stockholders will receive in the merger depends on the market price of CIENA common stock at the time of the merger. In addition, for the holders of Catena’s preferred stock, the number of shares allocated to each class also depends upon the average closing price of CIENA’s common stock over the 30-day period ending three days prior to closing. The market price of CIENA common stock may decline, causing the value of the consideration received by Catena stockholders in the merger, and the number of shares to be issued to holders of Catena’s preferred stock, to decline. The market price of CIENA common stock is extremely volatile and has fluctuated over a wide range. From March 22, 2003 to March 22, 2004, CIENA common stock traded as high as $8.14 per share and as low as $4.19 per share. From February 18, 2004, the last trading day prior to the date on which the merger was announced, through March 22, 2004, the price of CIENA common stock has decreased from $6.28 per share to $4.77 per share, a decline of approximately 24%. The market price of CIENA common stock may continue to fluctuate significantly in response to various factors, including:

	•	quarterly variations in operating results principally due to customer purchasing decisions;
	•	changes in estimates by securities analysts;
	•	continued low levels in capital spending by customers; and
	•	general economic conditions.

Directors and officers of Catena may have conflicts of interest that influenced their decisions to approve the merger.

      You should be aware of potential conflicts of interest of, and the benefits available to, directors and executive officers of Catena when considering the Catena board of directors’ recommendation of the merger agreement and the other proposals. Some directors and executive officers of Catena have interests in the merger and the other proposals that are in addition to, or different from, their interests as Catena stockholders. These interests are described under “The Merger  — Interests of Executive Officers and Directors in the Merger” on page 27.

      These interests include:

	•	Executive Officer Benefits. Each of Catena’s executive officers may benefit from acceleration of vesting and severance benefits implemented in connection with the merger. Catena’s executive officers entered into severance benefits agreements with Catena, which agreements would be obligations assumed by CIENA in the merger. Each such agreement provides that if the officer is terminated without cause or terminates his or her employment for good reason, (a) all vesting restrictions with respect to his or her options and stock would lapse, (b) he or she would receive a severance payment equal to six months of salary and (c) he or she would receive continuation or subsidization of certain medical benefits for up to six months following termination.
	•	Distribution of Proceeds in Merger. As a result of the amendment and restatement of Catena’s certificate of incorporation and the terms of the merger agreement, holders of Catena common stock may receive more consideration in the merger than they would if it were treated as an “Acquisition” or “Asset Transfer” of Catena constituting a “liquidation” under Catena’s existing certificate of incorporation if the average closing price of CIENA’s common stock over the 30-day period ending three days prior to the merger is less than $7.82. The majority of Catena’s outstanding common stock is held by executive officers of Catena. Conversely, if the average closing price of CIENA’s common stock over the 30-day period ending three days prior to the merger is

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		greater than $7.82, the holders of Catena’s preferred stock would receive more shares of CIENA common stock than they would if the merger were treated as an “Acquisition” or “Asset Transfer” of Catena constituting a “liquidation” under Catena’s existing certificate of incorporation. The majority of Catena’s outstanding preferred stock is held by affiliates of directors of Catena.
	•	Indemnification. Under the merger agreement, CIENA has agreed to provide continued indemnification for present and former directors and officers of Catena with respect to matters existing prior to the closing of the merger, for six years following the closing, including matters relating to the merger.
	•	Stockholder Agreements. All Catena directors and officers (and their respective affiliates) have entered into stockholder agreements pursuant to which they have agreed to vote shares of Catena common and preferred stock over which they exercise voting control in favor of the adoption of the merger agreement and the merger and in favor of approval of the amendment and restatement of Catena’s certificate of incorporation. The stockholder agreements also grant to CIENA an irrevocable option to purchase a portion of the shares of Catena stock that are owned beneficially or of record by the stockholders who entered into the stockholder agreements.

      The structure and implementation of the merger involve a number of risks including risks of integration and unknown liabilities.

      The merger involves the combination of CIENA with a private company with limited operating history and is a complex transaction. Among the risks the merger involves are risks of successful integration, potential liabilities that may be incurred as a result of the merger, tax consequences and accounting treatment.

      Successful integration involves numerous risks, including:

	•	assimilating Catena’s technology and product offerings, which may be more difficult than anticipated because the technology is complex;
	•	coordinating research and development efforts, which may involve unexpected problems;
	•	diversion of management attention from business matters to integration issues;
	•	identifying and retaining key personnel, which may be difficult in the combined company;
	•	integrating accounting, engineering, information technology and administrative systems, which may be unexpectedly difficult or costly;
	•	making significant cash expenditures that may be required to retain personnel, eliminate unnecessary resources and integrate the business;
	•	maintaining uniform standards, controls, procedures and policies, which may be harder than CIENA and Catena anticipate and interfere with efficient administration of the combined company; and
	•	changes in the businesses as a result of the merger that impair relationships with employees, customers or vendors.

      In addition, as a result of the merger, CIENA will succeed to any liabilities of Catena now existing or arising out of Catena’s businesses prior to closing, including unknown liabilities. These liabilities may include liabilities to customers, suppliers or employees, as well as potential liabilities that can arise from intellectual property disputes.

      Further, CIENA is proposing to issue up to 24.1 million shares of common stock to acquire another private company, Internet Photonics, Inc., at approximately the same time as the acquisition of Catena and all of the risks described above exist with respect to that acquisition as well.

      Failure to overcome these risks or any other problems encountered in connection with the merger could have a material adverse effect on CIENA’s business, results of operations and financial condition.

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      Only in limited circumstances can Catena terminate the merger due to a decrease in CIENA’s stock price.

      Catena can terminate the merger agreement if the average closing price of CIENA’s common stock listed on the Nasdaq National Market for the 10 trading days immediately preceding the date stockholder approval is obtained is less than $3.12. Otherwise, neither party has the right to terminate the merger solely due to increases or decreases in CIENA’s stock price, even if those fluctuations would materially affect the value of the consideration Catena stockholders will receive in the merger.

FORWARD-LOOKING STATEMENTS

      Some of the statements contained, or incorporated by reference, in this proxy statement/ prospectus discuss future expectations, contain projections of results of operations or financial condition or state other “forward-looking” information. Those statements are subject to known and unknown risks, uncertainties and other factors that could cause the actual results to differ materially from those contemplated by the statements. The “forward-looking” information is based on various factors and was derived using numerous assumptions. In some cases, you can identify these so-called “forward-looking statements” by words like “may,” “will,” “should,” “expects,” “plans,” “anticipates,” “believes,” “estimates,” “predicts,” “potential,” or “continue” or the negative of those words and other comparable words. You should be aware that those statements only reflect our predictions. Actual events or results may differ substantially. Important factors that could cause our actual results to be materially different from the forward-looking statements are disclosed under the heading “Risk Factors” beginning on page 10 and throughout this proxy statement/ prospectus.

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THE SPECIAL MEETING OF CATENA NETWORKS, INC. STOCKHOLDERS

General

      Catena is furnishing this proxy statement/ prospectus to its stockholders in connection with the solicitation of proxies by the Catena board of directors for use at the special meeting of stockholders of Catena to be held on [                              ], 2004, and at any adjournment or postponement thereof. This document is also being furnished to Catena stockholders by CIENA as a prospectus of CIENA in connection with the issuance by CIENA of shares of CIENA common stock as contemplated by the merger agreement.

      This document was first mailed to stockholders of Catena on or about [                              ], 2004.

Date, Time and Place

      The special meeting will be held on [                              ], 2004 at 8:00 a.m., local time, at the offices of Catena at 307 Legget Drive, Kanata, Ontario, Canada. Catena’s telephone number is
(613) 599-6430.

Purpose of the Special Meeting

      The purpose of the Catena special meeting is to consider and vote upon proposals to:

      1. Approve and adopt the merger agreement;

      2. Approve and adopt the amendment and restatement of Catena’s certificate of incorporation to provide that the merger of Catena into CIENA is not an “Acquisition” or “Asset Transfer” of Catena that would be treated as a “liquidation” of Catena as defined therein;

      3. Approve the payments to [                               ] of amounts that would otherwise result in “parachute payments” under Section 280G of the Tax Code;

      4. Grant discretionary authority to the Catena board of directors to adjourn or postpone the Catena special meeting to solicit additional votes to approve the matters considered at the special meeting, if necessary; and

      5. Consider and act upon any other matter that may properly come before the special meeting.

A copy of the merger agreement is included in this proxy statement/ prospectus in Annex A. Catena stockholders are encouraged to read the merger agreement in its entirety.

Record Date and Voting

      Holders of record of common stock and preferred stock of Catena at the close of business on                     , 2004 (referred to in this proxy statement/ prospectus as the record date) that are entitled to vote at any annual or special meeting of Catena stockholders, are entitled to vote at the special meeting and any adjournment or postponement of the special meeting. Holders of non-voting common stock and series B-1, series BB-1, series C-1, series CC-1, series D-1 and series DD-1 preferred stock are not entitled to vote at the special meeting. Holders of all classes and series of Catena’s common stock and preferred stock are entitled to notice of the matters proposed to be voted on at the special meeting.

      On the record date, the following voting securities were outstanding:

	•	[9,371,695] shares of voting common stock;
	•	[10,100,000] shares of series A preferred stock;
	•	[440,000] shares of series A-1 preferred stock;
	•	[7,677,856] shares of series B preferred stock;

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	•	[7,514,978] shares of series C preferred stock; and
	•	[61,982,888] shares of series D preferred stock.

      Each share of common stock entitled to vote at the special meeting is entitled to one vote on each matter brought properly before the special meeting. Each share of preferred stock entitled to vote at the special meeting is entitled to a number of votes equal to the number of shares of common stock into which such share of preferred stock would be convertible pursuant to Catena’s certificate of incorporation (assuming such shares were currently convertible). Each share of series A preferred stock is entitled to one vote for each matter brought properly before the special meeting. Each share of series A-1 preferred stock is entitled to approximately 1.13 votes for each matter brought properly before the special meeting. Each share of series B preferred stock is entitled to approximately 1.63 votes for each matter brought properly before the special meeting. Each share of series C preferred stock is entitled to approximately 1.98 votes for each matter brought properly before the special meeting. Each share of series D preferred stock is entitled to one vote for each matter brought properly before the special meeting. However, as described below, approval of the merger agreement and the amendment and restatement of Catena’s certificate of incorporation requires special votes of preferred stockholders, including certain “unaffiliated investors.”

      Generally, the representation, in person or by properly executed proxy, of the holders of a majority of all the shares of capital stock issued and outstanding and entitled to vote at the Catena special meeting is necessary to constitute a quorum for the transaction of business at the Catena special meeting. In connection with the separate vote by the voting preferred stock, a majority of the total outstanding shares of such series of capital stock present in person or represented by proxy shall constitute a quorum entitled to take action at the Catena special meeting. In connection with the separate vote by the series C preferred stock, a majority of the total outstanding shares of such series of capital stock present in person or represented by proxy shall constitute a quorum entitled to take action at the Catena special meeting. In connection with the separate vote by the holders of common stock, a majority of the total outstanding shares of common stock present in person or represented by proxy shall constitute a quorum entitled to take action at the Catena special meeting. If you sign and send in your proxy card and do not indicate how you want to vote, it will be voted in favor of the merger agreement and in favor of the other proposals.

      Under Delaware law and the certificate of incorporation of Catena, approval of the merger agreement and of the amendment and restatement of Catena’s certificate of incorporation requires the affirmative vote of:

	•	holders of a majority of Catena’s common stock entitled to vote at any annual or special meeting of Catena stockholders;
	•	holders of a majority of Catena’s common stock and preferred stock that are entitled to vote at any annual or special meeting of Catena stockholders, voting together as a single class on an as-converted into common stock basis; and
	•	holders of a majority of Catena’s voting preferred stock, voting together as a single class on an as-converted basis into common stock, including at least three unaffiliated investors.

      In addition, under Catena’s certificate of incorporation, adoption of the amendment and restatement of Catena’s certificate of incorporation requires the affirmative votes of the holders of at least 70% of the outstanding shares of series C preferred stock.

      In order to ensure that certain payments made to certain U.S. executive officers of Catena are not treated as “parachute payments,” the affirmative vote of more than 75% of the voting power of all outstanding capital stock of Catena (other than stock held by the disqualified individuals) is required to approve these payments. Under the applicable Treasury Regulations, approval by a stockholder that is not an individual (i.e., an entity) of a payment generally must be made by the person authorized by the entity stockholder to approve the payment (assuming such authorized person is not a “disqualified individual”).

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      Abstentions from voting identified as such on the proxy card are treated as present or represented for purposes of determining the presence or absence of a quorum at the special meeting. However, abstentions as to a proposal will have the same effect as votes against such proposal.

      As of the close of business on the record date for the special meeting, Catena’s directors and executive officers (and their respective affiliates) held approximately                     shares of Catena voting common stock and                     shares of Catena voting preferred stock on an as-converted into common stock basis, or approximately [          ]% and [          ]% of the shares of Catena’s common stock and preferred stock entitled to vote at the special meeting. In addition, directors, executive officers and stockholders of Catena beneficially owning as of the record date:

	•	[6,155,675] shares of voting common stock, representing approximately [66]% of Catena’s common stock entitled to vote at any annual or special meeting of Catena stockholders;
	•	[63,036,614] shares of voting common stock and voting preferred stock considered on an as-converted into common stock basis, representing approximately [57]% of Catena’s common stock and preferred stock entitled to vote at any annual or special meeting of Catena stockholders, on an as-converted into common stock basis; and
	•	[56,880,939] shares of voting preferred stock considered on an as-converted into common stock basis, representing approximately [56]% of Catena’s voting preferred stock, on an as-converted into common stock basis, and [54%] of the series C preferred stock,

have entered into agreements, pursuant to which they have agreed to vote their Catena shares in favor of adoption and approval of the merger agreement and approval of the amendment and restatement of Catena’s certificate of incorporation, against any proposal made in opposition to, or in competition with, the merger, and against any proposal intended to impede, frustrate, prevent or nullify the merger, or that could reasonably be expected to change the voting rights of the capital stock. As of the close of business on the record date, neither CIENA nor any officer or director of CIENA owned shares of Catena common or preferred stock.

Voting of Proxies at the Special Meeting and Revocation of Proxies

      All shares of Catena capital stock that are entitled to vote and are represented at the Catena special meeting by properly executed proxies received prior to or at such meeting, and not revoked, will be voted at such meeting in accordance with the instructions indicated on such proxies. If no instruction is indicated, such proxies will be voted “FOR” approval and adoption of the merger agreement, “FOR” the amendment and restatement of Catena’s certificate of incorporation, “FOR” approval of the payments that would otherwise result in “parachute payments,” and “FOR” the grant of discretionary authority to adjourn or postpone the special meeting to solicit additional votes to approve the matters considered at the special meeting, if necessary.

      The Catena board of directors does not know of any matters other than those described in the notice of the Catena special meeting that are to come before such meeting. If any other matters are properly presented at the Catena special meeting for consideration, the persons named in the enclosed proxy card and acting thereunder generally will have discretion to vote on such matters in accordance with their best judgment.

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      Any proxy given pursuant to the solicitation may be revoked by the person giving it at any time before it is voted. Proxies may be revoked by:

	•	filing with Kevin Forbes, the Secretary of Catena, at or before the taking of a vote at the Catena special meeting, a written notice of revocation bearing a later date than the proxy,
	•	duly executing a later dated proxy relating to the same shares and delivering it to Kevin Forbes before the taking of the vote at the Catena special meeting, or
	•	attending the Catena special meeting and voting in person (although attendance at the Catena special meeting will not in and of itself constitute a revocation of a proxy).

      Any written notice of revocation or subsequent proxy should be sent to Catena Networks, Inc., 307 Legget Drive, Kanata, Ontario K2K 3C8, Canada, Attn: Kevin Forbes, Secretary, or hand-delivered to Kevin Forbes at or before the taking of the vote at the Catena special meeting.

      Catena will be soliciting proxies on its own behalf. Catena intends to solicit proxies through this proxy statement/ prospectus and directly through its directors, officers and regular employees. Solicitation of some stockholders may be made in person or by mail, telephone, facsimile transmission or other means of electronic transmission.

      Catena will bear its own expenses in connection with the solicitation of proxies for its special meeting of stockholders, except that CIENA will bear all printing and filing costs and expenses, other than attorneys’ and accountants’ fees and expenses of Catena. CIENA will bear all other expenses incurred in connection with the preparation of this document and the preparation and filing of the registration statement of which this document forms a part.

Quorum and Abstentions

      The representation in person, or by properly executed proxy, of the holders of a majority of all shares of capital stock entitled to vote at the special meeting is necessary to constitute a quorum for the transaction of business at the special meeting of Catena. In connection with the separate vote by the voting preferred stock, a majority of the total outstanding shares of the voting preferred stock (considered on an as-converted into common stock basis) present in person or represented by proxy shall constitute a quorum entitled to take action at the Catena special meeting. In connection with the separate vote by the series C preferred stock, a majority of the total outstanding shares of such series of capital stock present in person or represented by proxy shall constitute a quorum entitled to take action at the Catena special meeting. In connection with the separate vote by the holders of Catena’s voting common stock, a majority of the total outstanding shares of Catena’s voting common stock present in person or represented by proxy shall constitute a quorum entitled to take action at the Catena special meeting.

      Shares held by persons abstaining will be counted in determining whether a quorum is present at the Catena special meeting. Catena has appointed Kevin Forbes, its Secretary, to function as the inspector of elections of the special meeting. The inspector of elections will ascertain whether a quorum is present, tabulate votes and determine the voting results on all matters presented to Catena stockholders at the special meeting. If a quorum is not present, or fewer shares of Catena common and preferred stock are voted for the approval of the proposals being considered at the special meeting, and if stockholders approve the grant of discretionary authority to the Catena board of directors to adjourn the special meeting, the special meeting may be postponed or adjourned for the purpose of allowing additional time for obtaining additional proxies or votes, and, at any subsequent reconvening of the special meeting, all proxies will be voted in the same manner as the proxies would have been voted at the original convening of the special meeting, except for any proxies that have been effectively revoked or withdrawn prior to the subsequent reconvening of the special meeting.

      If you submit a proxy that indicates an abstention from voting in all matters, your shares will be counted as present for the purpose of determining the existence of a quorum at the special meeting, but they will not be voted on any matter at the applicable special meeting. Consequently, your abstention will

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Board of Directors Recommendation

      The Catena board of directors has unanimously determined that the merger agreement, the amendment and restatement of Catena’s certificate of incorporation and the payment of “parachute payments” to certain U.S. executive officers of Catena are advisable, fair to and in the best interests of Catena and its stockholders. Accordingly, the Catena board of directors has unanimously approved the merger agreement, the amendment and restatement of Catena’s certificate of incorporation and the payment of “parachute payments” to certain of its U.S. executive officers and unanimously recommends that stockholders vote “FOR” adoption and approval of the merger agreement, “FOR” adoption and approval of the amendment and restatement of Catena’s certificate of incorporation, “FOR” approval of the payments that would otherwise result in “parachute payments,” and “FOR” approval of the grant of discretionary authority to adjourn the special meeting to solicit additional votes if necessary. In considering such recommendations, Catena stockholders should be aware that some Catena directors and officers have interests in the merger that are different from, or in addition to, those of Catena stockholders, and that Catena and CIENA have provided indemnification arrangements to directors and officers of Catena. See “The Merger — Interests of Executive Officers and Directors in the Merger.”

      The matters to be considered at the special meeting are of great importance to the stockholders of Catena. Accordingly, Catena stockholders are urged to read and carefully consider the information presented in this document and to complete, date, sign and promptly return the enclosed proxy in the enclosed, postage-paid envelope.

      Catena’s stockholders should not send any stock certificates with their proxy cards. A transmittal form with instructions for the surrender of Catena common stock certificates will be mailed to Catena stockholders promptly following completion of the merger. For more information regarding the procedures for exchanging Catena stock certificates for CIENA stock certificates, see “Terms of the Merger Agreement and Related Transactions — Exchange of Certificates; Fractional Shares.”

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THE MERGER

General

      The boards of directors of CIENA and Catena have each approved the merger agreement, which provides for the merger of Catena with and into CIENA, with CIENA being the surviving corporation of the merger. Each share of Catena common stock and Catena preferred stock outstanding immediately prior to the merger will be converted into the right to receive shares of CIENA common stock. The shares of Catena common stock and Catena preferred stock will be converted into a number of shares of CIENA common stock in accordance with the formulas specified in the merger agreement, as described under “Terms of the Merger Agreement and Related Transactions — Treatment of Stock, Options and Warrants.” Fractional shares of CIENA common stock will not be issued in connection with the merger, and Catena stockholders otherwise entitled to a fractional share will be paid in cash for the fractional share, in the manner described under “Terms of the Merger Agreement and Related Transactions — Exchange of Certificates; Fractional Shares.”

Background of the Merger

      As a regular part of their business, CIENA and Catena from time to time have each independently considered opportunities to expand and strengthen their own technology, products, research and development capabilities and distribution channels, including distribution agreements, acquisitions, investments, licenses, development agreements and joint ventures. In particular, CIENA’s senior management has been interested in pursuing broadband services as a potential addressable market segment, and from time to time CIENA has had contact with various parties to explore on a preliminary basis strategic alternatives in connection with the same.

      On June 4, 2003, at the Supercomm 2003 trade show in Atlanta, Georgia, Beth Perry, then CIENA’s Senior Vice President Business Development, and Byron BeMiller, CIENA’s Senior Director, Business Development, met with Gudmundur Hjartarson, President and Chief Executive Officer of Catena, and Gary Bolton, Vice President of Marketing for Catena, both of whom provided a brief overview of Catena’s business and financial outlook.

      The next day, on June 5, 2003, Mr. BeMiller and Steve Chaddick, CIENA’s Senior Vice President and Chief Strategy Officer, Steve Alexander, CIENA’s Senior Vice President and Chief Technology Officer, and Tom Mock, CIENA’s Senior Vice President of Strategic Planning, visited Catena’s booth at Supercomm and met with Messrs. Hjartarson and Bolton. Topics of discussion included Catena’s products, technology and market.

      Subsequently, CIENA and Catena entered into a general nondisclosure agreement.

      In the summer of 2003, Catena received preliminary inquiries from several telecommunications equipment providers other than CIENA regarding potential strategic partnerships or acquisitions. At that time, Catena was also beginning to evaluate the prospect of effecting an initial public offering of its common stock in 2004.

      In July 2003, Jim Collier, CIENA’s Senior Vice President, Corporate Development, spoke with Mr. Bolton about the potential for some form of business arrangement between the two companies. Mr. Bolton indicated that Mr. Hjartarson wished to speak directly with Gary B. Smith, CIENA’s President and Chief Executive Officer, to gauge the level of CIENA’s interest in a potential business arrangement with Catena.

      On July 22, 2003, Mr. Smith spoke with Mr. Hjartarson and indicated that CIENA was interested in pursuing discussions with Catena and, to that end, arranged for a meeting between the principals of both parties.

      On August 1, 2003, Messrs. Smith, Alexander and Collier, and Joseph Chinnici, CIENA’s Senior Vice President, Finance and Chief Financial Officer, met with Messrs. Hjartarson and Bolton and Kevin

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      On September 10, 2003, Messrs. BeMiller and Mock, Arpit Joshipura, CIENA’s Vice President of Portfolio Solutions Marketing, and Dan Spears, CIENA’s Director, Strategic Planning, visited Catena’s offices in Kanata, Ontario, Canada to gather more detailed information on Catena and its products and technology. Catena was represented by Messrs. Hjartarson, Bolton and Forbes, as well as Mark Feeley, Vice President, System Development, Jonathan Boocock, Vice President, Line Circuit Development, and Andy Weirich, Vice President, System Architecture. During the meeting, Catena gave a presentation on its products and technology, financial information, and current and future market opportunities. The parties also had a preliminary discussion about the potential for an acquisition of Catena by CIENA. Over the next several weeks, the parties continued to provide each other with additional business and financial information.

      On September 16, 2003, Catena retained the services of Goldman, Sachs & Co. as financial advisor to Catena in connection with a potential acquisition of Catena. Entities affiliated with Goldman Sachs hold shares of Catena stock.

      On October 8, 2003, the parties entered into a new nondisclosure agreement, incorporating a provision prohibiting the solicitation of each other’s employees.

      On October 15, 2003, at a regularly scheduled meeting of Catena’s board of directors, Catena management reported to the board of directors regarding their meetings with several investment banks relating to a potential initial public offering of Catena’s common stock. The board was advised of the criteria these banks indicated were necessary for Catena to effect a successful initial public offering in 2004.

      In October and November 2003, Catena’s financial advisor contacted six telecommunications equipment providers in addition to CIENA that were identified by Catena and its financial advisor as being most likely to be interested in acquiring Catena. Of those six companies, four requested and were sent additional information regarding Catena. However, only CIENA indicated a continued interest in further discussions regarding an acquisition of Catena. In this regard, on October 30, 2003, Messrs. Collier and Hjartarson met at Catena’s offices in Canada to discuss a potential business combination between the parties. Mr. Collier informed Mr. Hjartarson that CIENA would be interested in a possible business combination, provided that the parties could agree on mutually acceptable business terms, and Mr. Hjartarson indicated Catena was prepared to entertain negotiations with CIENA, although it continued to explore the alternative of an initial public offering. Messrs. Collier and Hjartarson also discussed the possible valuation of Catena in connection with a transaction, as well as potential synergies between the two companies.

      In November 2003, CIENA engaged Morgan Stanley to act as its financial advisor in connection with a proposed transaction with Catena.

      On November 21, 2003, CIENA sent Catena a draft of a non-binding letter of intent with respect to a proposed transaction.

      On December 3, 2003, Messrs. Smith and Collier met with Mr. Hjartarson at CIENA’s offices in Linthicum, Maryland, to discuss specifics regarding the proposed transaction, including a possible purchase price. Also present at this meeting for CIENA were Emil Savov, Vice President, Corporate Development, and CIENA’s financial advisors from Morgan Stanley, and for Catena, Mr. Forbes and Catena’s financial advisors from Goldman Sachs.

      On December 4, 2003, at a regularly-scheduled meeting of Catena’s board of directors, the board of directors discussed the terms of CIENA’s letter of intent. After considering all appropriate factors and circumstances, the board of directors determined that the proposed purchase price put forth by CIENA was insufficient. After such discussion, the board of directors authorized Goldman Sachs to deliver a

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      Subsequently, CIENA proposed a revised purchase price and other terms to Catena.

      In December 2003, Goldman Sachs continued its discussions with many of the companies (other than CIENA) that had originally been contacted regarding Catena. In the course of these discussions, none of the companies contacted indicated an interest in pursuing an acquisition of Catena.

      On December 15, 2003, at a special meeting of Catena’s board of directors, Mr. Hjartarson and Goldman Sachs updated the board of directors regarding the revised terms proposed by CIENA. At this meeting, the board of directors reviewed and considered the revised terms proposed by CIENA and discussed with Goldman Sachs the possible range of reasonable IPO valuations of Catena and the likely timeframe for effecting an initial public offering. After such discussion, the board of directors authorized Goldman Sachs to deliver a counterproposal to CIENA bearing certain revisions to the letter of intent discussed at the meeting.

      Subsequently, CIENA proposed a revised purchase price and other terms to Catena.

      On December 18, 2003, at a special meeting of Catena’s board of directors, Mr. Hjartarson and Goldman Sachs updated the board of directors regarding the newly revised terms proposed by CIENA. After such discussion, the Board authorized Goldman Sachs to deliver another counterproposal to CIENA bearing further revisions to the letter of intent discussed at the meeting. The board of directors also authorized Mr. Hjartarson, with the assistance of Goldman Sachs and legal counsel, to further negotiate and enter into a non-binding letter of intent comporting with the terms discussed by the board of directors.

      On December 24, 2003, Mr. Smith spoke with Mr. Hjartarson regarding the terms of the letter of intent being discussed.

      On December 31, 2003, CIENA and Catena entered into a non-binding letter of intent, which provided, among other things, for a proposed purchase price of 75,000,000 shares of CIENA common stock for all of the equity of Catena on a fully-diluted basis.

      On January 6, 2004, at a special meeting of the CIENA board of directors, CIENA’s senior management and representatives of Morgan Stanley discussed with the board the status of conversations with Catena regarding a possible business combination, including the strategic and financial reasons for such a combination and the key terms from the letter of intent. After discussion, the CIENA board of directors expressed general support for the strategic value of an acquisition of Catena, and authorized management to continue discussions with a view toward reaching a definitive agreement on acceptable terms.

      On January 8, 2004, CIENA’s legal advisors from Hogan & Hartson commenced a legal due diligence review of Catena, which continued through January 14, 2004.

      On January 12, 13 and 14, 2004, a CIENA due diligence team conducted a series of meetings with Catena representatives in Ottawa, Ontario. CIENA representatives at one or more of those meetings included Messrs. Chinnici, BeMiller, Savov and Joshipura; Jésus Léon, Senior Vice President and Chief Development Officer; Arthur Smith, Senior Vice President Global Operations; Lynn Moore, Vice President Human Resources; Phil Moser, Vice President Sales Operations; Chad Whalen, Vice President Sales; Francois Locoh-Donou, Vice President Marketing; Suzanne DuLong, Vice President Investor Relations; Andrew Petrik, Vice President Finance; Greg Sikon, Vice President Tax; David Rothenstein, Assistant General Counsel; Vijay Sharma, Director Sales; Ralph Masso, Lead Accountant; Nancy Macartney, Senior Operations Director; Rick Conklin, Principal Engineer P&T; Venkata Rangavajhala, Management P&T; and Rebecca Seidman, Human Resources Consultant. CIENA’s financial advisors from Morgan Stanley, CIENA’s legal advisors from Hogan & Hartson, and representatives from PricewaterhouseCoopers, CIENA’s independent accountants, were also present at one or more of those meetings. Catena representatives at one or more of those meetings included Messrs. Hjartarson, Bolton, Boocock, Feeley, and Forbes, Richard DeGabrielle, Vice President Sales and Business Development, Jeffrey Reece, Vice President Operations, Jennifer Kaufield, Assistant Vice President Finance, and Franca

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      On January 14, 2004, Mr. Smith contacted Mr. Hjartarson to advise him that CIENA had entered into a non-binding letter of intent with Internet Photonics, Inc. and was in the process of negotiating a possible acquisition of that company.

      On January 15, 2004, at a special meeting of Catena’s board of directors, Mr. Hjartarson briefed the Catena board of directors on the Ottawa due diligence meetings with CIENA. Catena’s financial advisor and legal counsel briefed the board of directors on the expected timing and process for negotiating definitive acquisition agreements. The board of directors also discussed the level of due diligence review that should be performed with respect to CIENA. It was then agreed that a business due diligence session should be scheduled to take place in Linthicum, Maryland prior to the execution of the definitive merger agreement.

      On January 16, 2004, CIENA directed Hogan & Hartson to send to Catena and Cooley Godward a first draft of a definitive merger agreement, stockholder voting agreements and related agreements.

      On January 20, 2004, Cooley Godward sent to CIENA comments on the draft of the merger agreement and related agreements on behalf of Catena.

      During late January and early February 2004, representatives of CIENA and Catena and their respective legal advisors continued to negotiate the merger agreement and related agreements.

      On February 3, 2004, CIENA announced its preliminary results for the first fiscal quarter ended January 31, 2004, and reported revenue that was below CIENA’s previously announced guidance range. On the same day, Mr. Smith spoke with Mr. Hjartarson to advise him of the announcement and the reasons for it.

      On February 9, 2004, a Catena due diligence team conducted meetings with CIENA representatives at CIENA’s offices in Linthicum, Maryland. Catena was represented by Messrs. Hjartarson and Feeley, as well as three members of the Catena board of directors, Gary Morgenthaler, Joseph Costello and John Jarve. CIENA representatives included Messrs. Smith, Chinnici, Collier and Moser. Financial advisors for Catena and CIENA were also present at those meetings.

      On February 10, 2004, at a special meeting of Catena’s board of directors, the Catena board discussed the outcome of the February 9th due diligence session, including their impressions of the business prospects of CIENA in the near term and the relative value to the combined company that would be offered by Catena. The board of directors concluded that while it continued to believe a transaction with CIENA was advisable to Catena and its stockholders, the relative value to the combined company provided by Catena would be greater than originally anticipated and thus the proposed purchase price should be increased to reflect the increase in relative value. After such discussion, the board of directors authorized Goldman Sachs to inform CIENA’s financial advisor that the number of shares issuable in the merger would need to be increased in order to enter into a definitive merger agreement with Catena. This information was communicated by Goldman Sachs to Morgan Stanley on February 11, 2004.

      Between February 11 and February 12, 2004, the parties held numerous telephone discussions, including those between Messrs. Smith and Hjartarson and between the parties’ respective financial advisors, regarding the number of shares CIENA would be willing to issue for all of the equity of Catena on a fully-diluted basis. On February 11, 2004, members of Catena’s board of directors discussed the status of negotiations with CIENA over the number of shares offered by CIENA. After such discussion, Mr. Hjartarson contacted Mr. Smith to negotiate the final number of shares issuable in the merger and all remaining business issues with respect to the merger agreement. On February 12, 2004, Messrs. Hjartarson and Smith discussed an increase in the proposed purchase price and agreed on a purchase price of 77,500,000 shares of CIENA common stock.

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      On February 16, 2004, Mr. Smith met with Messrs. Hjartarson, Boocock, Feeley and Weirich and Andrew Deczky, Catena’s Chief Scientist, at CIENA’s offices in Linthicum, Maryland, to discuss their respective roles in the combined company following the close of the merger and other merger specific matters.

      On February 16, 17 and 18, 2004, representatives of CIENA and Catena completed negotiations on the merger agreement and related agreements and discussed the proposed charter amendments and other actions being taken to carry out the terms of the merger.