November 22, 2022The world's first successful optical switching of 15-mode multiplexed signals by spatial optical switch prototypeA group of researchers from the Network Research Institute of the National Institute of Information and Communications Technology (NICT, Japan) led by Ruben Soares Luís, along with its partners, has achieved the first demonstration of a field deployed 15-mode optical fiber network, equivalent to 15 parallel fiber networks using a single fiber installed in the city of L'Aquila, Italy.This was equivalent to implementing 15 parallel optical fiber networks using a single fiber and a single network node, demonstrating the potential for spatial division multiplexing (SDM) systems to greatly extend the capacity of current fiber networks in a realistic environment.This demonstration shows that mode-multiplexing over multi-mode fibers with a standard cladding diameter, which are compatible with current cabling technologies and have a high spatial channel count, can be adopted in deployed networks and is a significant step toward the realization of a backbone communication systems to support various information communication services after Beyond 5G.A transmitter and the WXC node supporting 15-mode multiplexed signals were located in the facilities of the University of L'Aquila and connected to a field-deployed 6.1 km 15-mode fiber ring.Although mode multiplexing requires digital signal processing at the receiver to compensate for a mode mixing, a mode-multiplexed network utilizing multi-mode fibers with standard diameters can provide a high-density, high-capacity network at low cost."