Tang Xizi, Chen You-Wei, Zhang Rui, Yao Shuang, Zhou Qi, Shen Shuyi, Guo Mengqi, Qiao Yaojun, Chang Gee-Kung
Opt Lett. 2020 Nov 15;45(22):6278-6281. doi: 10.1364/OL.401437.
In this Letter, we experimentally demonstrate a 50// four-level pulse amplitude modulation-based passive optical network system with a 10 G class receiver. A memory polynomial equalizer (MPE) combined with a decision feedback equalizer (DFE) is applied to eliminate channel distortions in the system. To further improve the performance of the MPE-DFE, for the first time, to the best of our knowledge, a low-complexity hybrid decision scheme (HDS) is proposed, which consists of single-symbol decision (SSD) and multi-symbol decision (MSD). The SSD is exactly the conventional hard decision based on minimum Euclidean distance, whereas MSD is based on a simplified maximum likelihood detection principle with M-algorithm. In terms of complexity, MSD requires 19.1% more multiplications than SSD, but the symbol number of MSD only accounts for less than 20% of the total signal frame when the received optical power is greater than -27. Experimental results show that the proposed MPE-DFE with HDS achieves a 0.7 dB and 1.3 dB sensitivity gain compared with conventional SSD, and up to 35.4 dB and 31.4 dB link power budget, regarding the forward error correction threshold of 10 and 10, respectively.
在本信函中，我们通过实验展示了一种基于50 // 四电平脉冲幅度调制的无源光网络系统，该系统配备了10 G类接收器。采用了一种将记忆多项式均衡器（MPE）与判决反馈均衡器（DFE）相结合的方法来消除系统中的信道失真。为了进一步提高MPE - DFE的性能，据我们所知，首次提出了一种低复杂度混合判决方案（HDS），它由单符号判决（SSD）和多符号判决（MSD）组成。SSD正是基于最小欧几里得距离的传统硬判决，而MSD基于具有M算法的简化最大似然检测原理。在复杂度方面，MSD比SSD所需的乘法运算多19.1%，但当接收光功率大于 - 27时，MSD的符号数仅占总信号帧的不到20%。实验结果表明，与传统的SSD相比，所提出的带有HDS的MPE - DFE在误码率为10和10时，灵敏度增益分别达到0.7 dB和1.3 dB，链路功率预算分别高达35.4 dB和31.4 dB。
