This paper proposes optimal finite-length impulse response (FIR) digital filters, in the least-squares (LS) sense, for compensation of chromatic dispersion (CD) in digital coherent optical receivers. The proposed filters are based on the convex minimization of the energy of the complex error between the frequency responses of the actual CD compensation filter and the ideal CD compensation filter. The paper utilizes the fact that pulse shaping filters limit the effective bandwidth of the signal. Then, the filter design for CD compensation needs to be performed over a smaller frequency range, as compared to the whole frequency band in the existing CD compensation methods. By means of design examples, we show that our proposed optimal LS FIR CD compensation filters outperform the existing filters in terms of performance, implementation complexity, and delay.
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机译：本文提出了一种最小二乘（LS）意义上的最佳有限长度脉冲响应（FIR）数字滤波器，用于补偿数字相干光接收机中的色散（CD）。所提出的滤波器是基于实际CD补偿滤波器和理想CD补偿滤波器的频率响应之间的复误差能量的凸最小化。本文利用了脉冲整形滤波器限制信号有效带宽这一事实。然后，与现有CD补偿方法中的整个频带相比，用于CD补偿的滤波器设计需要在较小的频率范围内执行。通过设计实例，我们表明，我们提出的最佳LS FIR CD补偿滤波器在性能，实现复杂性和延迟方面优于现有滤波器。
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