[34][35] In 2003, a federal court jury determined that Corvis Corporation, another fiber optic telecommunications equipment provider established by Huber in 1997, infringed a patent owned by Ciena.

Fourteen of AstraCom's engineers signed four-year contracts with Ciena, and joined the company's new research and development team in Alpharetta, Georgia.

Alta's engineering and installation products were used by service providers for switching, transport, and wireless communications; the company continued to operate as a subsidiary of Ciena.

[40][41][42] Ciena purchased Terabit Technology Inc., a producer of detectors for data transmission based in Santa Barbara, California,[43] for $11.7 million in April 1998.

[47][48] ONI Systems, a San Jose, California–based producer of phone and computer data equipment, was acquired by Ciena for $900 million in stock in June 2002.

[33][34][49] The acquisitions of Cyras, which produced optical switch systems, and ONI, which made transport equipment for data transfer, allowed Ciena to focus on networks in metropolitan areas.

[50] Ciena purchased WaveSmith Networks Inc., an optical-networking equipment manufacturer based in Acton, Massachusetts, for $158 million in stock in 2003.

Akara expanded Ciena's product line and storage networking capabilities, and continued to operate as a subsidiary.

Catena had approximately 220 employees at the time,[55] and the purchase of Internet Photonics marked Ciena's entrance into the cable industry.

[56] In 2008, Ciena acquired World Wide Packets Inc. (WWP), a Spokane Valley, Washington–based producer of switches and software for Ethernet services, for approximately $296 million.

WWP offered the LightningEdge operating system and network management tools, and had more than 100 customers in 25 countries at the time.

WWP became a whole owned subsidiary, and the company's office and 65 employees in Spokane, Washington were used by Ciena until mid 2018.

[12][58][59] Nortel's Metro Ethernet Networks business developed next-generation optical-transmission equipment and had more than 1,000 customers in 65 countries at the time.

[12] Ciena acquired Cyan, which offers platforms and software systems for network operators, for approximately $400 million in 2015.

[61][62] The assets of TeraXion Inc., a network management system company based in Quebec City, were purchased for $32 million in 2016.

[4] Ciena and Sify partnered in mid 2018 to increase the information and communications technology company's network capacity from 100G to 400G.

[68] In 2019, Bharti Airtel used Ciena equipment to build a 130,000 km photonic control plane network, connecting more than 4,000 locations in India.

[69][70] Ciena provides converged packet optical and Ethernet services to Bharti Airtel, Jio, and Vodafone Idea Limited, and supplies equipment to the Government of India, as of mid 2019.