All-Optical Transparent Forwarding Relay System for Interstellar Optical Communication Networks

An all-optical forwarding relay (AOFR) system is proposed to provide an arbitrary forward with multiple channels and demonstrated by incorporating multiple acquisition, tracking, and pointing (ATP) systems and an arbitrary optical forwarding system (AOFS) with eight channels carrying passive loads. The insertion loss and arbitrary switching time of the AOFS are tested to be <1.1 dB and similar to 3 ms, respectively. The number of hops, bit error rate, and Q factor are evaluated with three modulation formats, 997 Mb/s 16-QAM, 27 Gb/s BPSK, and 54 Gb/s QPSK. The results indicate that the connection time of the optical communication is reduced to a few milliseconds by using the rapid arbitrary channel switching and the pre-point of ATP systems. In addition, the AOFR system is fully transparent to the channel wavelengths, forwarding ports, data rates, and modulation formats. To the best of our knowledge, the proposed AOFR system demonstrates the first arbitrary channel forwarding solution for large-capacity passive load among satellites, which will be an enabling solution for future interstellar optical communication networks.