Raman Crosstalk Suppression in NG-PON2 Using Optimized Spectral Shaping

In this paper, we present an innovative proposal to mitigate the effect of Raman crosstalk in the interaction between NG-PON2 TWDM-PON channels and legacy RF-video by electrical spectral shaping on the TWDM NRZ data stream obtained through electrical FIR filtering. We find an analytical and closed form solution on FIR filter taps that, for a given target spectral shaping, gives the absolute minimum amount of intersymbol interference on the TWDM data. Then, we propose techniques to implement these FIR filters with reasonable system complexity. We found that our proposed technique is applicable to all classes (up to E2 PON, +11 dBm transmitted downstream power) with less than 0.5 dB power penalty on TWDM channels even in the worst-case scenario of RF-video still based on analog channels on the lower part of the spectrum.