Low-density parity-check codes used for polarization mode dispersion mitigation in 40-Gb/s optical fiber system

Instead of Reed-Solomon (RS) code, Low-density parity-check (LDPC) codes are used with distributed fast polarization scramblers (FPSs) for polarization mode dispersion (PMD) mitigation in 40-Gb/s optical fiber system. The scrambling speed of FPS for LDPC (2040, 1903) codes system is discussed, the optimal speed 10MHz is obtained. The correction performance of LDPC codes are compared with RS codes. Results show the LDPC code can achieve a better performance than the RS (255, 239) code at a similar redundancy with soft decoding.