Outage Probability Due to PDL Using Threshold Exceedances: Implications of DD-LMS Equalization and Inter-Channel Fiber Nonlinearities

The outage probability due to polarization dependent loss (PDL) is estimated using the method of threshold exceedances for a multi-channel transmission model that includes i) decision-directed least-mean-square equalization to partially compensate PDL, ii) the dominant fiber nonlinear effects of cross-phase modulation and cross-polarization modulation, and iii) transceiver noise. The outage probability is defined in terms of the bit-wise achievable information rate (BW-AIR) being less than a threshold value for the generalized mutual information determined by the forward error correcting code rate. The root mean square error between the mean excess function and a theoretical fit to it is used for the critical step of determining the threshold below which the BW-AIR data is represented by the generalized Pareto distribution. The applicability of the method of threshold exceedances is demonstrated for 32 Gbaud, dual-polarization 64-ary quadrature amplitude modulation with a uniform constellation.