CIENA CORP

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of

the Securities Exchange Act of 1934

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Ciena Corp oration

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PROXY STATEMENT

2025 Annual Meeting

of Stockholders

Ciena Corporation

Hanover, Maryland 21076

Notice of Annual Meeting of Stockholders

To the Stockholders of Ciena Corporation:

The 2025 Annual Meeting of Stockholders of Ciena Corporation (the "Annual Meeting") will be held on March 27, 2025 at 3:00 p.m. Eastern Time. Our Annual Meeting will be a virtual meeting held over the Internet. You will be able to attend the Annual Meeting, vote your shares electronically and submit your questions during the live webcast of the meeting by visitingwww.virtualshareholdermeeting.com/CIEN2025 and entering your 16-digit control number included in the notice containing instructions on how to access Annual Meeting materials, your proxy card, or the voting instructions that accompanied your proxy materials.

Items of Business

1.Elect two members of the Board of Directors from the nominees named in the accompanying proxy statement to serve as Class I directors for three-year terms ending in 2028, or until their respective successors are elected and qualified.2.Ratify the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for fiscal 2025.3.Conduct an advisory vote on our named executive officer compensation, as described in these proxy materials.4.Consider and act upon such other business as may properly come before the Annual Meeting or any adjournment or postponement thereof.

These matters are more fully described in the proxy statement accompanying this notice. You are entitled to notice of, and are eligible to vote at, this year’s Annual Meeting if you were a stockholder of record as of the close of business on January 27, 2025.

In accordance with Securities and Exchange Commission rules, we are furnishing these proxy materials and our Annual Report to Stockholders for fiscal 2024 via the Internet. On or about February 13, 2025, stockholders as of the record date are first being mailed a Notice of Internet Availability of Proxy Materials with instructions on how to access our Annual Meeting materials and vote via the Internet, by mail, or by telephone.

We believe that your vote, and the vote of every Ciena stockholder, is important. Whether or not you plan to participate in the Annual Meeting, we encourage you to review the accompanying proxy statement for information relating to each of the proposals and to cast your vote promptly.

By Order of the Board of Directors,

Sheela Kosaraju

Senior Vice President, General Counsel and Assistant Secretary

Hanover, Maryland

February 13, 2025

This notice of annual meeting, proxy statement and accompanying form of proxy card are being made available on or about February 13, 2025.

Table of contents

Cautionary note regarding forward-looking statements

This proxy statement contains certain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), that are based on current expectations, forecasts, assumptions and other information available to Ciena Corporation ("Ciena" or "we") as of the date hereof. Forward-looking statements involve inherent risks and uncertainties, include statements regarding Ciena’s expectations, beliefs, intentions or strategies regarding the future, including with respect to business, financial, operational, compensation and sustainability and governance matters, and can be identified by forward-looking words such as "anticipate," "believe," "can," "could," "continue," "estimate," "expect," "future," "goal," "intend," "may," "plan," "potential," "should," "will," and "would" or similar words. Ciena’s actual results, performance or events may differ materially from these forward-looking statements made or implied due to a number of risks and uncertainties relating to Ciena’s business, including the effect of broader economic and market conditions on Ciena’s customers and their business, Ciena’s ability to execute its business and growth strategies and to achieve sustainability goals, the impact of macroeconomic conditions, and the risks and uncertainties discussed in Ciena’s Annual Report on Form 10-K for fiscal 2024 ("2024 Form 10-K") as well as Ciena’s other filings with the Securities and Exchange Commission (the "SEC"). Ciena undertakes no obligation to revise or update any forward-looking statements made in this proxy statement, whether as a result of new information, future events or circumstances, or otherwise, except as required by law.

Information contained on or available through our website is not incorporated by reference in or made part of this proxy statement and any references to our website are intended to be inactive textual references only.