PHASE NOISE AND POLARIZATION STATE INSENSITIVE OPTICAL COHERENT SYSTEMS

In the last few years, optical coherent systems have been extensively investigated and demonstrated. However, to spread their use, practical and cost-effective solutions must be found to solve the fundamental problems of phase noise and polarization state change. In this paper, we present three different schemes that allow compensation of both effects by sending a reference channel that is suitably frequency shifted by using polarization modulation together with Stokes parameters detection or computing and inverting the Jones matrix that describes the fiber polarization state transformation. As a conclusion, some comparisons are made among different approaches in order to show how different systems can be tailored to different requirements both in point-to-point and in multipoint networks. © 1990 IEEE