Li Haibo, Zeng Tao, Li Jie, Jiang Feng, Liu Ziqing, Hu Rong, Luo Ming, Wang Yuanxiang, Li Xiang, Yang Qi, Yu Shaohua, Huang Liyan, Cao Li
Opt Express. 2016 Jul 25;24(15):16609-17. doi: 10.1364/OE.24.016609.
In this paper, we propose a novel manipulated rotating polarization switched quadrature phase shift keying (MR-PS-QPSK) technique, and corresponding correlated constant modulus algorithm (CMA) for signal recovery. The latter utilizes the correlation between the PS-QPSK symbols in the two polarizations to lock the phase of output signals. Then the signals in the two polarizations are merged according to the recovered switching bit, which suppresses the noise and simplifies the subsequent process. A field programmable gate array (FPGA) based real-time platform is built for experimental demonstration. The experimental results show that the proposed MR-PS-QPSK modulation format with correlated CMA can provide 3.2 dB optical signal-to-noise ratio (OSNR) improvement over dual-polarization QPSK (DP-QPSK) at back-to-back case and 3.8 dB OSNR improvement after fiber transmission at the same symbol rate, which corresponds to be about 2 dB OSNR improvement at the same bit rate. The resource consumption analysis in FPGA digital signal processing blocks and logic utilizations shows that the MR-PS-QPSK with correlated CMA only requires a small additional computational effort.
在本文中，我们提出了一种新颖的可控旋转偏振切换正交相移键控（MR-PS-QPSK）技术以及用于信号恢复的相应相关恒模算法（CMA）。后者利用两个偏振态中PS-QPSK符号之间的相关性来锁定输出信号的相位。然后根据恢复的切换比特合并两个偏振态中的信号，这抑制了噪声并简化了后续处理。构建了一个基于现场可编程门阵列（FPGA）的实时平台用于实验演示。实验结果表明，所提出的具有相关CMA的MR-PS-QPSK调制格式在背对背情况下比双偏振QPSK（DP-QPSK）可提供3.2 dB的光信噪比（OSNR）改善，在相同符号率下经过光纤传输后可提供3.8 dB的OSNR改善，这相当于在相同比特率下约2 dB的OSNR改善。对FPGA数字信号处理模块中的资源消耗分析和逻辑利用率表明，具有相关CMA的MR-PS-QPSK仅需要少量额外的计算量。
