NEC, OCC, Sumitomo partner on multicore fiber submarine cable trial

Oct. 4, 2021

Paired with space-division multiplexing (SDM) transmission, such multicore fiber could help meet future submarine network capacity requirements, the companies posit.

Stephen Hardy

NEC Corp. (TSE: 6701), its subsidiary OCC Corp., and Sumitomo Electric Industries, Ltd. (TSE: 5802) reported that they are the first to trial uncoupled four-core multicore submarine cable. Paired with space-division multiplexing (SDM) transmission, such multicore fiber could help meet future submarine network capacity requirements, the companies posit.

Multicore fiber can increase the number of parallel optical fiber cores in a system without increasing the submarine cable size and structure, say the companies. The uncoupled four-core fiber deployed in this case used the OCC SC500 series LW (lightweight) cable, which has a 17-mm outer diameter and is designed to operate at depths up to 8,000 m. The cable can accommodate up to 32 fibers – but four-core fiber would provide significant capacity expansion within such a fiber count, the companies point out.

NEC and OCC demonstrated that the cable's optical transmission performance in the water meets the performance requirements of modern long-haul submarine cables. They also demonstrated that the cabling of Sumitomo Electric's multicore fiber had no effect on its optical characteristics.

The companies point out that the use of uncoupled multicore fiber cables is a key component of future success for the technology. Optical signals propagating in the respective cores of coupled multicore fiber tend to interfere with each other, they say, and thus would require additional signal processing at the optical receiver. Uncoupled multicore fibers minimize the interference between the cores, which enables the use of conventional transmitters and receivers.

Japan’s Ministry of Internal Affairs and Communications (MIC) supported the demonstration as part of its "Research and Development of Innovative Optical Network Technology for a Novel Social Infrastructure" (JPMI00316) initiative.

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About the Author

Stephen Hardy | Editorial Director and Associate Publisher, Lightwave

Stephen Hardy is editorial director and associate publisher of Lightwave and Broadband Technology Report, part of the Lighting & Technology Group at Endeavor Business Media. Stephen is responsible for establishing and executing editorial strategy across the both brands’ websites, email newsletters, events, and other information products. He has covered the fiber-optics space for more than 20 years, and communications and technology for more than 35 years. During his tenure, Lightwave has received awards from Folio: and the American Society of Business Press Editors (ASBPE) for editorial excellence. Prior to joining Lightwave in 1997, Stephen worked for Telecommunications magazine and the Journal of Electronic Defense.

Stephen has moderated panels at numerous events, including the Optica Executive Forum, ECOC, and SCTE Cable-Tec Expo. He also is program director for the Lightwave Innovation Reviews and the Diamond Technology Reviews.

He has written numerous articles in all aspects of optical communications and fiber-optic networks, including fiber to the home (FTTH), PON, optical components, DWDM, fiber cables, packet optical transport, optical transceivers, lasers, fiber optic testing, and more.

You can connect with Stephen on LinkedIn as well as Twitter.