CIENA to Join Nasdaq-100 Index Beginning August 4, 1999

Linthicum, MD — 07/29/1999

Ciena Corporation (NASDAQ: CIEN) today announced that it will become a component of the Nasdaq-100 Index effective the beginning of trading on Wednesday, August 4, 1999.

In addition, shares of Ciena will be included in the Nasdaq-100 Index SharesSM (Amex: QQQ), the Nasdaq-100 Index Tracking StockSM, which are securities that represent ownership in the Nasdaq-100 Trust. The Trust holds a portfolio of equity securities that comprise the Nasdaq-100 Index and aims to provide investment results that generally correspond with its performance. Ciena replaces Quantum Corporation, which is delisting from The Nasdaq Stock Market®.

With a market capitalization of approximately $4.6 billion, Ciena's market-leading intelligent optical networking systems form the core for the new era of telecommunications networks. Ciena's LightWorks™ architecture changes the fundamental economics of service provider networks by simplifying the network and reducing the cost to operate it.

The Nasdaq-100 Index includes 100 of the largest non-financial domestic companies listed on the Nasdaq National Market tier of The Nasdaq Stock Market, Inc. The Index reflects Nasdaq's largest growth companies across major industry groups. The Nasdaq-100 Index was launched in January 1985 and rose more than 80 percent in 1998, although past performance is not necessarily indicative of future performance and Index performance does not represent the performance of Nasdaq-100 Shares. The Nasdaq-Amex Market GroupSM, which operates The Nasdaq Stock Market and the American Stock Exchange® (Amex®), is a subsidiary of the National Association of Securities Dealers, Inc. (NASD®), the largest securities-industry, self-regulatory organization in the United States.