Polarization-Dependent Loss Impact on Coherent Optical Systems in Presence of Fiber Nonlinearity

We investigate the interaction of polarization-dependent loss (PDL) with Kerr nonlinearities by decoupling single- and cross-channel nonlinear distortions in a homogeneous 100-G polarization division multiplexing quadrature phase shift keying (PDM-QPSK) and a hybrid 100-G PDM-QPSK/10-G on/off keying system. Because of the decoupling method, we provide reasons for the interaction, using basic comprehensive examples. Both average Q-factor and its distribution are investigated in both dispersion-managed and dispersion-unmanaged links, showing that realistic PDL values affect outage probabilities notwithstanding a negligible average penalty.