RZ-DPSK传输系统相位噪声的比较分析

建立了单信道40Gbit／s归零-差分相移键控码（RZ-DPSK）传输系统模型，详细地分析并比较了线性相位噪声和非线性相位噪声对系统性能的影响。结果表明，由放大器自发辐射（ASE）噪声带来的线性相位噪声对传输系统的性能影响最大，ASE与自相位调制（SPM）相互作用引起的Gordon-Mollenauer（G-M）相移次之，带内四波混频（IFWM）的影响最小。在最优输入功率的条件下，由ASE带来的线性相位噪声引起的系统差分相位Q值代价大于204dB，由G-M相移引起的系统差分相位Q值代价小于7．5dB。仿真结果表明，对于采用掺铒光纤放大器（EDFA）级联放大的单信道40Gbit／s RZ-DPSK传输系统，ASE噪声是限制系统无中继传输距离的最主要因素。

Comparison of the Phase Noise of Single Channel 40 Gbit/s RZ-DPSK Transmission System

The influences of linear and nonlinear phase noise on the performance of single channel 40 Gbit/s RZ-DPSK transmission system were analyzed in detail. The result showed that the linear phase noise induced by ASE noise was of the most significant influence, the nonlinear phase shift induced by self phase modulation took the second place ,and IFWM had the least influence. With optimum input power, the differential phase Q-factor penalty was more than 204 dB for ASE-induced linear phase noise and less than 7.5 dB for G-M phase shift. The result showed that the ASE-induced linear phase noise was the major limmitation to DPSK transmission systems with lumped EDFA amplifiers.