Optimized optical filtering for 40 Gb/s/channel enhanced phase-shaped binary transmission in ultra dense WDM systems

The systematic optimization of multiplexing (MUX) and demultiplexing (DMUX) 3 dB filter bandwidths for enhanced phase-shaped binary transmission (EPSBT) coding format is performed. Long-haul 40 Gb/s ultra dense wavelength division multiplexing (UDWDM) system with 0.8 bit/s/Hz spectral efficiency is shown to be achievable with different filter types. By extensive numerical optimization of MUX and DMUX filtering, we show that the optimum EPSBT has an extinction ratio parameter of 0 dB for second-order super Gaussian filters and between 2 and 6 dB for Gaussian filters.