Novel configuration of finite-impulse-response filters tolerant to carrier-phase fluctuations in digital coherent optical receivers for higher-order quadrature amplitude modulation signals.
Novel configuration of finite-impulse-response filters tolerant to carrier-phase fluctuations in digital coherent optical receivers for higher-order quadrature amplitude modulation signals.
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DOI：
10.1364/oe.20.026236
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发表时间：
2012-11
期刊：
影响因子：
3.8
通讯作者：
Y. Mori;Chao Zhang;K. Kikuchi
中科院分区：
文献类型：
--
作者：
Y. Mori;Chao Zhang;K. Kikuchi
提出了一种基于相位相关判决引导最小均方（DD-LMS）算法的数字相干光接收机有限冲激响应（FIR）滤波器的新结构。由于快速载波相位波动被从误差信号中去除，从而更新FIR滤波器的抽头系数，因此可以实现高阶正交幅度调制（QAM）信号的滤波器抽头系数的稳定自适应。计算机仿真表明，我们提出的方案是更宽容的相位噪声和频率偏移比传统的DD-LMS方案。这样的理论预测也验证了实验使用10-Gsymbol/s的双极化16-QAM信号。
We propose a novel configuration of the finite-impulse-response (FIR) filter adapted by the phase-dependent decision-directed least-mean-square (DD-LMS) algorithm in digital coherent optical receivers. Since fast carrier-phase fluctuations are removed from the error signal which updates tap coefficients of the FIR filter, we can achieve stable adaptation of filter-tap coefficients for higher-order quadrature-amplitude modulation (QAM) signals. Computer simulations show that our proposed scheme is much more tolerant to the phase noise and the frequency offset than the conventional DD-LMS scheme. Such theoretical predictions are also validated experimentally by using a 10-Gsymbol/s dual-polarization 16-QAM signal.