将π旋转型低密度奇偶校验(LDPC)码应用于100Gb/s偏振复用差分正交相移键控(PDM-DQPSK)光通信系统中,进行了相应的数值仿真和性能分析比较,其中采用打孔技术得到了高码率的改进码型,并在纠错性能方面与原始码型进行了对比。在译码方面,推导了PDM-DQPSK系统的卡方统计模型,并与高斯统计模型进行了对比。结果表明,码率为0.5的π旋转型LDPC码在采用卡方统计信道概率模型时性能最佳,可使系统光信噪比(OSNR)在14.2dB时保证误码率(BER)在10-9以下;在2dB的OSNR代价情况下,系统可容忍102ps/nm的色度色散(CD)、18ps的一阶偏振模色散(PMD),以及4.88×10-2 rad的非线性引起的最大相位偏移,由此可知π旋转型LDPC码可以极大地提高高速光通信系统的传输可靠性。 The π-rotating low density parity check (LDPC) code is applied to the 100Gb / s polarization multiplexing differential quadrature phase shift keying (PDM-DQPSK) optical communication system, and the corresponding numerical simulation and performance analysis are compared, The improved code pattern with high bit rate was obtained by puncturing technology, and compared with the original code pattern in error correction performance. In decoding, the chi-square statistical model of PDM-DQPSK system is deduced and compared with Gaussian statistical model. The results show that the π-rotated LDPC codes with a code rate of 0.5 have the best performance when using the chi-square statistical channel probability model, and the bit error rate (BER) of the OSNR of 14.2dB can be guaranteed at 10- 9; the system can tolerate 102ps / nm Chromatic Dispersion (CD), 18ps First Order PMD, and 4.88 × 10-2 rad nonlinear maximum induced phase at 2dB OSNR cost Offset, it can be seen that the π-rotation type LDPC code can greatly improve the transmission reliability of a high-speed optical communication system.