Sliding window aided phase noise suppression method for coherent Nyquist-WDM-PON

Digital coherent Nyquist wavelength division multiplexed passive optical network (Nyquist-WDM-PON), which guarantees very high spectrum efficiency by Nyquist pulse shaping, is a strong candidate for future access PONs. In order to match the low-cost target, the cheap large-linewidth lasers are chosen as the optical source in NG-PON2. However, the induced phase noise by the lasers can seriously cut down the system performance. In this letter, we propose a sliding window aided method to suppress the effect caused by phase noise and introduce it into a typical coherent Nyquist-WDM-PON. With the help of our proposed method, the demand for laser linewidth can be reduced significantly, which justifies the extensive application of cost-effective coherent Nyquist-WDM-PON in the future.