非线性相位噪声即高登米勒（G-M）效应是限制相位调制系统传输距离的一个重要因素。系统地研究了G-M效应对单信道速率为40 Gb/s的相干正交频分复用（CO-OFDM）系统的影响。理论分析了在不同的链路参数（入纤功率、跨段距离和色散系数）配置下，放大自发辐射（ASE）噪声沿链路的分布是如何影响系统性能的，并通过搭建CO-OFDM系统的仿真平台，对系统性能进行了仿真研究，比较了两种不同的光纤系统（标准单模光纤系统和非零色散位移光纤系统）中G-M效应的差别。研究发现，G-M效应随着入纤功率的增大而增强。相同的传输长度，跨段距离越小，G-M效应越严重。链路中的累积色散对G-M效应有一定的抵抗作用。

Nonlinear phase noise, i.e., Gordon-Mollenauer (G-M) effect can limit the transmission distance for phase-shift-keying modulation formats. The effect of G-M noise in 40 Gb/s coherent orthogonal frequency division multiplexing (CO-OFDM) system is researched systematically. Based on the CO-OFDM system platform, amplified spontaneous emission (ASE) noise distributed in the fiber link under different parameters is simulated and theoretically analyzed. The difference of G-M noise in two kinds of optical fiber systems [single-mode fiber (SMF) and non-zero dispersion shifted fiber (NZDSF) systems] is compared with the same parameter settings. The results show that G-M effect will enhance with the increase of input power. For the same span length, the shorter distance of one span, the more serious the G-M effect. And the residual chromatic dispersion of system can suppress the G-M effect.