Long-haul WDM transmission of 448 Gbit/s polarisation-division multiplexed 16-ary quadrature amplitude modulation using coherent detection

The transmission of a PDM-QAM16 signal at 400 Gbit/s over 1200 km in a WDM environment is demonstrated. The WDM link carrying 40 PDM-QAM16 channels modulated at the same bit rate incorporates ultra-low-loss, large effective area fibre and erbium-doped fibre amplifiers.