Transmission benefits of multicore fiber in submarine cables to be discussed at OFC 2022

Feb. 3, 2022

A team at NEC Corp. have developed and tested what they assert is the first uncoupled four-core multicore fiber in a submarine cable.

Stephen Hardy

A team at NEC Corp. have developed and tested what they assert is the first uncoupled four-core multicore fiber in a submarine cable. A member of the NEC team will describe the prototype technology and demonstration results at the 2022 Optical Fiber Communication Conference and Exhibition (OFC) on Monday, March 7, 2022, in the San Diego Convention Center.

Team member Hitoshi Takeshita of the System Platform Research Laboratories at NEC will delivery the paper, which will describe a prototype that uses a SC520-type submarine cable. Such undersea cable can withstand water pressures at a depth of 8,000 meters and can hold 16 fiber pairs. The prototype cable contains 4 pairs of multicore fiber and 12 single-core pairs. The four-core multicore fiber has the same dimensions as single-core fiber. Thus each four-core fiber can carry four transmissions in the same fiber diameter as a single-core fiber, which enables an increase in cable capacity without affecting the cable size or reducing the number of fiber pairs.

To reduce inter-core crosstalk and improve signal attenuation, the NEC team integrated a multicore fiber amplifier into the cable. The amplifier as spliced directly with the fiber directly improved performance while minimizing cable bulk.

"It was never shown how multicore fiber would behave when cabled inside a submarine cable, with different bending and tension as it is usually evaluated in laboratory experiment," commented Takeshita via an OFC press release. "As submarine transmission is an ultralong haul, even slight variations of properties of cabled fiber have significant impact on the system performance as it accumulates with distance.

"Multicore fiber is now expected to further increase the number of parallel optical fiber cores without increasing the submarine cable size and structure, enabling the second generation of submarine SDM [space division multiplexing] systems," Takeshita added.

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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.