模分复用系统中的模式耦合和差分模式群时延对信号传输的影响, 需在接收端进行均衡补偿以实现信号可靠传输。与时域均衡相比, 频域均衡可有效降低DSP复杂度。基于频域盲均衡算法FD-CMA(frequency-domain constant modulus algorithm)和FD-MMA(frequency-domain multimodulus algorithm)在2×56 Gb/s 16 QAM模分复用系统中进行仿真对比。结果表明, 从星座图和误码性能角度来讲, FD-MMA对非常数模信号的均衡性能优于FD-CMA。在误比特率为10-3处, FD-MMA较FD-CMA有2.8 dB光信噪比的提升。

The effects of mode coupling and difference mode group delay on signal transmission in mode-division multiplexing system can be compensated with equalization to realize signal reliable transmission. Compared with time-domain equalization, frequency-domain equalization can effectively reduce digital signal processor (DSP) complexity. FD-CMA (frequency-domain constant modulus algorithm) and FD-MMA (frequency-domain multi-modulus algorithm) are used to simulate and compare in 2×56 Gb/s 16QAM mode-division multiplexing system. The results show that the equalization performance of FD-MMA is better than FD-CMA in constellation diagram and bit error rate (BER) performance. At the error bit rate of 10-3, FD-MMA has a 2.8 dB improvement of optical signal-to-noise ratio than FD-CMA.