Mousa-Pasandi Mohammad E, Plant David V
Photonic Systems Group, Department of Electrical and Computer Engineering, McGill University, Montreal, QC, H3A-2A7, Canada.
Opt Express. 2010 Sep 27;18(20):20651-60. doi: 10.1364/OE.18.020651.
We report and investigate the feasibility of zero-overhead laser phase noise compensation (PNC) for long-haul coherent optical orthogonal frequency division multiplexing (CO-OFDM) transmission systems, using the decision-directed phase equalizer (DDPE). DDPE updates the equalization parameters on a symbol-by-symbol basis after an initial decision making stage and retrieves an estimation of the phase noise value by extracting and averaging the phase drift of all OFDM sub-channels. Subsequently, a second equalization is performed by using the estimated phase noise value which is followed by a final decision making stage. We numerically compare the performance of DDPE and the CO-OFDM conventional equalizer (CE) for different laser linewidth values after transmission over 2000 km of uncompensated single-mode fiber (SMF) at 40 Gb/s and investigate the effect of fiber nonlinearity and amplified spontaneous emission (ASE) noise on the received signal quality. Furthermore, we analytically analyze the complexity of DDPE versus CE in terms of the number of required complex multiplications per bit.
我们报告并研究了使用判决导向相位均衡器（DDPE）对长距离相干光正交频分复用（CO-OFDM）传输系统进行零开销激光相位噪声补偿（PNC）的可行性。DDPE在初始判决阶段之后逐符号更新均衡参数，并通过提取和平均所有OFDM子信道的相位漂移来获取相位噪声值的估计。随后，使用估计的相位噪声值进行第二次均衡，之后是最终判决阶段。我们对在40 Gb/s下通过2000 km未补偿单模光纤（SMF）传输后不同激光线宽值的DDPE和CO-OFDM传统均衡器（CE）的性能进行了数值比较，并研究了光纤非线性和放大自发辐射（ASE）噪声对接收信号质量的影响。此外，我们从每比特所需复数乘法的数量方面，对DDPE和CE的复杂度进行了分析。
