Dunant Cable System Implements Space-Division Multiplexing (SDM) Technology

According to Google and SubCom, Google's Dunant cable system will implement SubCom’s space division multiplexing technology (SDM) and high fiber count (HFC) architecture. Dunant cable system will be the first ever in-service undersea cable featuring a 12 fiber-pair SDM design. Dunant will also deliver record-breaking capacity of 250 terabits per second across the Atlantic.

Traditional subsea cables are powered from the shore end and rely on a dedicated set of pump lasers to amplify the optical signal for each fiber pair as data traverses the length of the cable. Using SDM technology, pump lasers and associated optical components can share among multiple fiber pairs. In this way, the 6,400km-long Dunant cable system will add dedicated capacity, diversity and resilience to Google's global network, and will enable interconnection to other network infrastructure in the region.

SubCom will be first to market with HFC, power-efficient and capacity-optimized cable systems, which make use of the company’s SDM technology. SubCom repeaters incorporate SDM technology with an HFC solution that utilizes pump sharing amplifier architecture for increased system reliability and optimized cost-effective capacity.

This flexible architecture allows every amplifier to be supported by a combination of pump lasers, thus providing maximum overall capacity across 12FP, 16FP and 24FP trunk and branch segments.

Additionally, SubCom’s Wavelength Selective Switch (WSS) ROADM technology is now in production. WSS filter technology supports fully-flexible, reconfigurable routing of the optical spectrum on each fiber pair. This flexibility allows customers to dynamically reassign the optical spectrum between trunk and branches throughout the system’s life to achieve maximum value. Further flexibility is achieved using SubCom’s enhanced branching units (eBU) for optical path switching on up to 24FP branches.

The Dunant cable system is the second private submairne cable built by Google, following its first private and non-telecom submarine cable Curie, connecting Chile to Los Angeles.