Phys.org  March 8, 2019 The optical vortex carries the orbital angular momentum of light and can be used to multiplex signals by assigning each signal to a light wave of different momentum. Researchers in Japan designed and fabricated an orbital angular momentum multiplexing/demultiplexing module that could take five independent signals as input. Using a combination of two tiny circuit structures, called a star coupler and an optical-vortex generator, each of the five signals is “encoded” with a unique optical angular momentum. The output signal consists of a combination of the five signals, and the receiver circuit carries out the multiplexing […]