PERFORMANCE OF COHERENT OPTICAL POLARIZATION SHIFT KEYING MODULATION IN THE PRESENCE OF PHASE NOISE

The performance of optical coherent modulation schemes using the state of polarization of light as the modulating parameter (POLSK, POLariza tion Shift Keying) is analyzed, in the presence of laser phase noise. First, we compare three different analysis methods to account for the effects of phase noise in the binary case, and choose the one offering the best trade-off in terms of accuracy/complexity. Successively, we derive a tight upper bound to the performance of multilevel POLSK syst ems with postdetection filtering. Then, we include phase noise using t he best method as tested in the binary case and extensively discuss th e performance of binary and various multilevel POLSK constellations, o ptimized with respect to the IF filter bandwidth. The results show tha t binary POLSK has a very low sensitivity to phase noise and that mult ilevel POLSK is even less sensitive than tile binary scheme.