0.6Tbit/s Capacity and 2bit/s/Hz Spectral Efficiency at 42.6Gsymbol/s Using a Single DFB Laser with NRZ Coherent WDM and Polarisation Multiplexing

The capacity of a single-source coherent WDM (CoWDM) system is doubled from 298.2 Gbit/s to 596.5 Gbit/s by introducing polarisation multiplexing (PolMUX). This is achieved by generating a band of seven non-return-to-zero (NRZ) encoded channels at 42.6 Gsymbol/s. BER characterisations for single channel, 1 bit/s/Hz CoWDM channels and 2 bit/s/Hz CoWDM+PolMUX are performed. This work obtained high information spectral density of 2 b/s/Hz, allowing ISD's in excess of 1.8 b/s/Hz in a banded multi-Terabit/s system.