基于VDFE-RLS的单波长200 Gbit/s光接入系统(特邀)  

Single Wavelength 200 Gbit/s Downlink Optical Access System based on VDFE-RLS

作　　者：何婷 李响 李婕 罗鸣 HE Ting;LI Xiang;LI Jie;LUO Ming(School of Mechanical Engineering and Electronic Information,China University of Geosciences,Wuhan 430074,China;National Key Laboratory of Optical Communication Technologies and Networks,China Information Communication Technologies Group Corporation,Wuhan 430074,China)

机构地区：[1]中国地质大学机械与电子信息学院,武汉430074 [2]中国信息通信科技集团有限公司光纤通信技术和网络全国重点实验室,武汉430074

出　　处：《光通信研究》2024年第1期48-54,共7页Study on Optical Communications

基　　金：国家重点研发计划资助项目(2022YFB2903200)。

摘　　要：【目的】高速无源光接入网络中存在光纤色散、非线性损伤和带宽限制等问题,导致传统强度调制和直接检测技术的功率预算损失较高,难以满足高速无源光接入网络的要求。【方法】为了更好地提升强度调制和直接检测光接入系统的速率和性能,文章在Volterra判决反馈均衡器(VDFE)的基础上,研究了基于递推最小二乘估计(RLS)算法的VDFE-RLS信道均衡方法。该均衡器采用RLS算法对其中的抽头系数进行更新。该均衡器包含了一、二、三阶Volterra级数,其中一阶Volterra级数对线性损伤进行补偿,二阶和三阶Volterra级数能够对非线性损伤进行补偿。文章将该均衡器应用于经过20 km传输后的单波长为200 Gbit/s的O波段强度调制和直接检测技术的下行光接入系统中。【结果】实验结果表明,RLS算法相比传统的最小均方(LMS)算法在均衡器中表现出来的性能更好。此外,VDFE-RLS可以实现>29 dB的功率预算。VDFE-RLS相比于传统的基于Volterra的前馈均衡器(VFFE),当VDFE-RLS和VFFE-RLS均衡器长度相同时,可以实现2.2 dB功率预算的提升。当VDFE-RLS的均衡器长度为VFFE-RLS的一半时,前者相比后者仍可以提升0.5 dB的功率预算。【结论】文章所述系统相比其他传统系统在能够缩短均衡器长度的同时,能提高系统的功率预算,还能最终恢复出准确度较高的信号。【Objective】The optical fiber dispersion,nonlinear impairments and bandwidth limitation in high-speed passive optical access networks lead to high power budget loss in traditional intensity modulation and direct detection schemes,which are difficult to meet the requirements of future high-speed passive optical access networks.【Methods】In order to improve the speed and performance of the intensity modulation and direct detection optical access system,based on the Volterra Decision Feedback Equalizer(VDFE),this article studies the channel equalization method of VDFE-RLS based on Recursive Least Squares(RLS)algorithm.This equalizer uses RLS algorithm to update the tap coefficients.The equalizer includes a three-order Volterra series,allowing it to compensate for both linear and nonlinear impairments.In this paper,VDFE-RLS is applied to the downlink optical access system with a single wavelength 200 Gbit/s based on O-band intensity modulation and direct detection scheme after 20 km transmission.【Results】The experimental results show that the RLS has better performance than conventional Least Mean Square(LMS)algorithm in the equalization process.Besides,VDFE-RLS can achieve a power budget greater than 29 dB.When the length of the equalizer is the same,VDFE-RLS can increase the power budget by 2.2 dB compared with the conventional Volterra Feed Forward Equalization(VFFE)-RLS equalizer.When the length of VDFE-RLS equalizer is half that of VFFE-RLS,the VDFE-RLS can increase the power budget by 0.5 dB compared with the VFFE-RLS equalizer.【Conclusion】Compared with other traditional methods,the proposed method can shorten the length of the equalizer and increase the power budget of the system,and finally recover the signal with better performance.

关 键 词：Volterra判决反馈均衡器 递推最小二乘估计 VOLTERRA级数 自适应滤波算法 

分 类 号：TN915.6[电子电信—通信与信息系统]