Digital coherent optical receiver for satellite laser communication

Digital coherent methods are anticipated in next - generation optical communications. This paper discusses development of digital coherent optical transceivers for satellite laser communications. We attempt to apply digital filters, which have already shown results in ground optical fiber communications, to phase variations with atmospheric turbulence. For testing purposes, we developed phase modulators, 90-degrees hybrids for orthogonal polarization detection, an automatic optical frequency control circuit (AFC) and a digital signal processing (DSP) board based on field programmable gate array (FPGA). Communication performance is measured with QPSK at a transmission data rate of 12Gbps.