40 Gb/s Optical Single Sideband DWDM Transmission System using Polar Return-to-Zero Signalling Format

Optical single sideband (oSSB) 40 Gb/s transmission systems using binary polar coded return-to-zero (RZ) pulse shape are proposed to enable dense wavelength division multiplexing networks employing efficient electrical dispersion compensation (EDC). The detuning of ITU 50, 100, and 200 GHz grids optical filters is optimized by simulation. In presence of optical fibre and EDC, polar RZ oSSB clearly surpasses common nonreturn-to-zero oSSB for all the considered grids. After 160 km of standard single mode fibre, polar RZ retrieves
Q
-factors above 6 for the 50 GHz grid and above 7 for the remaining grids; whereas NRZ
Q
-factor is never superior to 3 after only 80 km.