22 September 2023

Sumitomo Electric Launches World’s First Mass-produced Ultra-low Loss, Multi-core Fiber

Sumitomo Electric Industries, Ltd. has realized the world’s first mass-production of ultra-low loss, multi-core fiber “2C Z-PLUS Fiber™ ULL,” and will launch its sales in October 2023.

Optical fiber is essential to the infrastructure supporting today’s information and telecommunications network society. With the widespread use of bandwidth-hungry network services including 5G mobile communications and global traffic between large-scale datacenters, it is essential to increase the capacity of optical communication systems. In order to expand transmission capacities further, multi-core fiber (MCF) that has plural cores in a single fiber has been actively studied and highly anticipated as a next-generation fiber.

By applying cutting-edge achievements in MCF R&D activities*¹and low-loss fiber technologies cultivated over 50 years*², Sumitomo Electric has developed and realized the world’s first mass-production of ultra-low loss MCF “2C Z-PLUS Fiber™ ULL*³.” While a conventional fiber has a single core in which optical signals propagate, 2C Z-PLUS Fiber™ ULL, as the name suggests, has two cores in the same outer dimensions as a conventional fiber. The transmission capacity through the 2C Z-PLUS Fiber™ ULL can be expanded twofold compared to a conventional single-core fiber because the two cores can carry optical signals independently. With a transmission loss of typically 0.158 dB/km at 1550 nm, the new fiber can be considered an ultra-low loss fiber (0.16 dB/km or less) applicable to a transoceanic submarine systems. A small counter-propagating inter-core cross-talk*⁴ of -43 dB or less is guaranteed. Also, 2C Z-PLUS Fiber™ ULL has equal outer diameters to a conventional single-core fiber (125 μm and 250 μm in glass and coating areas, respectively), and holds excellent environmental reliability and mechanical stability.

Table１　Typical characteristics of 2C Z-PLUS Fiber™ ULL

Glass diameter	125 μm
Coating diameter	250 μm
Transmission loss, at 1550 nm	0.158 dB/km
Effective area (Aeff), at 1550 nm	112 μm²
Cross-talk in counter-propagation, at C-band	≤ -43 dB

Cross-sectional photo of 2C Z-PLUS Fiber™ ULL.

＜Applications of 2C Z-PLUS Fiber™ ULL＞
・Broad areas of submarine network systems, from regional to transoceanic distances
・Long-haul, high-capacity terrestrial transmission
・Inter datacenter networks
・Ultra-low loss required applications:
quantum cryptography communications,sensor networks for seismic and fire detection.

Sumitomo Electric will continue to cultivate its world-leading R&D capabilities and mass-production technologies for optical fiber as an essential infrastructure of the information society, contributing to the realization of high-quality optical communications network systems.