Reference transmission and receiver optimization for coherent optical communication systems

The authors consider the performance of an optical communication system where an unmodulated reference signal is transmitted along with the information-carrying signal to alleviate the effect of phase noise. When the power of the two signals and the receiver bandwidths are optimized, the resulting performance is significantly better than that of traditional amplitude and frequency modulation schemes. This makes reference transmission with a joint optimization of signal and receiver parameters a promising scheme for coherent optical communications