NEC Corporation, along with its subsidiary OCC Corporation and Sumitomo Electric Industries, has stated that they have conducted the first testing of an uncoupled 4-core underwater fiber cable and confirmed its transmission performance to fulfill the stringent requirements of global telecommunications networks.   International data usage is anticipated to increase by 30-40%  by 2026, owing to reasons such as the expansion of 5G mobile data and the necessity to exchange ever more content between data centers located around the world. Submarine networks are using space division multiplexing (SDM) technology to fulfill this need, which increases the number of separate spatial channels to maximize the overall capacity of the system, decrease energy usage and minimize the cost per bit transferred. Multicore fiber is projected to increase the number of parallel optical fiber cores without changing the size and structure of underwater cables, allowing the introduction of second generation of submarine SDM…