Press Contacts: Paula Muezerie Ciena +44 20 7012 5640 [email protected] Richard Knowles BT +44 20 7356 5366 [email protected] Investor Contact: Gregg Lampf Ciena Corporation +1 (410) 694-5700 [email protected] FOR IMMEDIATE RELEASE BT and Ciena Light World’s First 800G Super-Channel Demonstrate future-proof nature of BT’s UK core optical transport network HANOVER, Md. and LONDON – May 23, 2013 – Ciena® Corporation (NASDAQ: CIEN), the network specialist, and BT, one of the world‟s leading communications services companies, today announced a series of pioneering trials over BT‟s UK optical core network infrastructure. The successful trials in March 2013 included the transmission of 100, 200, and 400G, as well as an „800G super- channel‟, the last of which equates to the simultaneous transmission of seven High Definition DVDs in a single second. Although transmission speeds have gone even higher in a laboratory environment, this milestone result was achieved over a deployed 410 km network link between BT‟s Adastral Park Research and Development Centre in Ipswich and the iconic BT Tower in Central London. Key Facts: BT and Ciena demonstrated support for Terabit-rate speeds over BT‟s core network with a series of 100, 200, 400, and 800G transmission trials using WaveLogic 3 transceivers - deploying both single and super-channel techniques. The trials were performed on a high Polarization Mode Dispersion (PMD) fibre link – which was unsuitable for traditional 10G operation – underlining the robustness of Ciena‟s coherent technology and its ability to be deployed in any environment. The trials demonstrate the future-proof nature of BT‟s core network – based on Ciena‟s 6500 Packet-Optical and 4200 Advanced Services platforms – which supports its entire product portfolio, including superfast broadband and Ethernet services. For one trial, 400G of traffic was carried and monitored over the network using 16QAM modulation, and operated flawlessly alongside adjacent 40G and 100G QPSK-based wavelengths, reinforcing the smooth migration path offered by Ciena‟s coherent technology. With Wavelogic 3, BT can gradually increase network capacity according to the requirements of its wholesale and business customers while lowering costs and minimising its carbon footprint. BT and Ciena partnership: Ciena has been a strategic supplier to BT since 2003 and its technology is used in BT‟s core infrastructure. The two parties entered into a strategic, multi-year collaboration agreement in January 2013 to jointly research and develop new applications and capabilities on BT‟s next generation network. Executive Quotes: “BT has always been a pioneer in the field of networking, and we can trace our roots back to the very first national telecommunications undertaking in the world – The Electric Telegraph Company. Since then, and with the recent explosion in global connectivity, we have constantly looked for new ways to future proof our infrastructure and provide more bandwidth for the next generation of applications and services. These trials prove that we‟re heading in the right direction, and we‟re very proud of our role in this latest milestone in the history of communications.” - Neil J. McRae, chief network architect at BT “These high capacity transmission demonstrations illustrate the value of Ciena and BT‟s long- standing strategic relationship. BT‟s future-proof network will enable it to stay ahead of the competition and continue to offer customers cutting-edge services, while minimising its overall cost-base and carbon footprint. With this collaboration agreement, we can further deepen our relationship and work together to build service-enabling and highly-programmable networks, leveraging Ciena‟s entire product portfolio to jointly develop ground-breaking services and applications for BT‟s customers.” - François Locoh-Donou, senior vice president, global products at Ciena Technology Leadership: Ciena is the pioneer and market leader of coherent optical technology with more than 20,000 coherent 40G/100G line interfaces shipped to over 100 customers across the globe, for a total deployment of more than 20 million coherent kilometers. Ciena‟s converged packet optical technology with WaveLogic Coherent Optical Processors gives service providers significant bandwidth scalability, reliability and network intelligence – all key building blocks of an OPn network architecture. Supporting Resources: Coherent Application Note: Coherent Optical Processing for High-Capacity Networks Video: Coherent Optical Processing Data Sheet: 6500 Packet-Optical Platform White Paper: OPn Network Architecture # # # About BT BT is one of the world‟s leading providers of communications services and solutions, serving customers in more than 170 countries. Its principal activities include the provision of networked IT services globally; local, national and international telecommunications services to its customers for use at home, at work and on the move; broadband and internet products and services and converged fixed/mobile products and services. BT consists principally of four lines of business: BT Global Services, BT Retail, BT Wholesale and Openreach. In the year ended 31 March 2013, BT Group‟s revenue was £18,017m with profit before taxation of £2,501m. British Telecommunications plc (BT) is a wholly-owned subsidiary of BT Group plc and encompasses virtually all businesses and assets of the BT Group. BT Group plc is listed on stock exchanges in London and New York. For more information, visit www.btplc.com. About Ciena Ciena is the network specialist. We collaborate with customers worldwide to unlock the strategic potential of their networks and fundamentally change the way they perform and compete. Ciena leverages its deep expertise in packet and optical networking and distributed software automation to delivering solutions in alignment with OPn, its approach for building open next-generation networks. We enable a high-scale, programmable infrastructure that can be controlled and adapted by network-level applications, and provide open interfaces to coordinate computing, storage and network resources in a unified, virtualized environment. We routinely post recent news, financial results and other important announcements and information about Ciena on our website. For more information, visit www.ciena.com. Note to Ciena Investors Forward-looking statements. This press release contains certain forward-looking statements based on current expectations, forecasts and assumptions that involve risks and uncertainties. These statements are based on information available to the Company as of the date hereof; and Ciena's actual results could differ materially from those stated or implied, due to risks and uncertainties associated with its business, which include the risk factors disclosed in its Report on Form 10-Q, which Ciena filed with the Securities and Exchange Commission on March 13, 2013. Forward-looking statements include statements regarding Ciena's expectations, beliefs, intentions or strategies regarding the future and can be identified by forward-looking words such as "anticipate," "believe," "could," "estimate," "expect," "intend," "may," "should," "will," and "would" or similar words. Ciena assumes no obligation to update the information included in this press release, whether as a result of new information, future events or otherwise. .