相干光通信中相位估计与信道均衡的联合使用
Combined use of phase estimation and channel equalization in coherent optical communications
摘要
在使用高阶相位调制的100 Gbit/s及以上速率的相干光通信系统中,激光器的相位噪声和光纤传输中的色散效应是影响系统性能的主要因素。为了补偿色散及相位噪声的影响,文章提出一种将电信道均衡与相位估计模块在电域联合使用的方法,相位估计在电信道均衡之后完成,其结果同时用于电信道均衡器的抽头系数更新。该方法可以有效降低对电信道均衡中迭代步长的要求,有助于系统获得更低的误码率和更稳定的误码性能,并且能够支持的传输距离也会增加。
Abstract
In the coherent optical communication systems at 100 Gbit/s and higher rates using high-order phase modulation, laser phase noise and dispersion effects in fiber-optic transmissions are the major factors that affect the system performance. To compensate for these effects, this paper proposes a method for the combined use of electric channel equalization and carrier phase estimation modules in the electric domain. The phase estimation is completed after the electric channel equalization, the results of which are also used in updating the tap coefficients of the equalizer. This method can effectively reduce the requirements for the step-size in the equalization, conducive to acquiring lower bit error rate, more stable error performance and longer transmission distance.
宋艳梅, 许渤, 邱昆. 相干光通信中相位估计与信道均衡的联合使用[J]. 光通信研究, 2012, 38(1): 6. Song Yanmei, Xu Bo, Qiu Kun. Combined use of phase estimation and channel equalization in coherent optical communications[J]. Study On Optical Communications, 2012, 38(1): 6.