用π旋转型低密度奇偶校验码提升100Gb/s偏振复用差分正交相移键控光通信系统性能  

Performance Enhancement of 100Gb/s Polarization Division Multiplexing Differenctial Quadrature Phase Shift Keying Optical Communication System withπ-Rotation Low-Density Parity-Check Codes

作　　者：毕伟[1] 席丽霞[1] 张晓光[1] 张文博[1] 

机构地区：[1]北京邮电大学信息光子学与光通信国家重点实验室,北京100876

出　　处：《中国激光》2014年第1期104-110,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(61205065);高等学校博士学科点专项科研基金(20110005110014)

摘　　要：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。π-rotation low-density parity-check （LDPC） code is applied in polarization division multiplexing differential quadrature phase shift keying （PDM-DQPSK） modulation optical fiber communication system. Performance analysis and comparison are conducted by numerical simulation, in which the same kind of codes with higher code rates are generated by employing puncturing technique and compared with primitive code in correction performance. With regard to decoding, the Chi-square statistical model of PDM-DQPSK is derived and compared with Gaussian one. The results exhibit that π-rotation LDPC codes can achieve their utmost performances when code rate is 0.5 and Chi-square statistical model is employed, which ensures bit error rate （BER） is below 10-9 while optical signal to noise ratio （OSNR） is 14.2 dB. When OSNR penalty is 2 dB, the system can tolerate 102 ps/nm chromatic dispersion, 18 ps first-order polarization mode dispersion and 4.88×10-2 rad nonlinear phase shift. The results indicate that π-rotation LDPC codes can enhance the transmitting reliability significantly.

关 键 词：光通信 π旋转型低密度奇偶校验码 偏振复用差分正交相移键控 前向纠错 信道概率模型 打孔技术 

分 类 号：TN911.22[电子电信—通信与信息系统]