Digital Coherent Receivers for Uncompensated 42.8Gbit/s Transmission over High PMD Fibre

We outline the principles behind digital coherent receivers and report simultaneous compensation of 53,712ps/nm chromatic dispersion from 3200km of SMF and a mean DGD up to 186ps using 42.8Gbit/s PDMQPSK with a digital coherent receiver.