Opt Express. 2023 Feb 13;31(4):5155-5166. doi: 10.1364/OE.470098.
Owing to the random birefringence of optical fibers, the recovery of the state of polarization (SOP) is urgently needed, especially in the nonlinear spectrum division multiplexing transmissions. Based on the variance of the polarization power ratio among symbols as the cost function, we propose a novel algorithm for the blind SOP recovery of eigenvalue communications. In the single eigenvalue transmissions with phase-shift keying or 16-ary amplitude and phase-shift keying constellations, at least 25.3 dB polarization extinction ratio can be achieved by using a block length of 30, even under 7 dB OSNR condition. It also shows that the proposed algorithm can be employed in multi-eigenvalue NFDM transmissions and full-spectrum modulated NFDM system. In the experiment, our proposed algorithm performs the same as the training symbol based method in back-to-back and less than 3000 km fiber link conditions; a maximum performance gain of 1.6 dB was obtained in ultra-long-haul condition (4300 km). It also shows that the impact of the polarization mode dispersion of a single-mode fiber on the algorithm is negligible.
由于光纤的随机双折射，偏振状态（SOP）的恢复迫在眉睫，特别是在非线性谱分复用传输中。基于符号间偏振功率比的方差作为代价函数，我们提出了一种用于特征值通信的盲 SOP 恢复的新算法。在具有相移键控或 16 进制幅度和相移键控星座的单个特征值传输中，使用长度为 30 的块，即使在 7 dB OSNR 条件下，也可以实现至少 25.3 dB 的偏振消光比。它还表明，所提出的算法可用于多特征值 NFDM 传输和全谱调制 NFDM 系统。在实验中，我们提出的算法在背靠背和小于 3000 km 光纤链路条件下与基于训练符号的方法性能相同；在超长距离（4300 km）条件下获得了 1.6 dB 的最大性能增益。它还表明，单模光纤的偏振模色散对算法的影响可以忽略不计。
