Impairment tolerance of 111 Gbit/s POLMUX-RZ-DQPSK using a reduced complexity coherent receiver with a T-spaced equaliser

The tolerance to narrow spectral filtering in presence of chromatic dispersion is investigated for 111Gbit/s POLMUX-RZ-DQPSK. It is shown that the use of T-spaced equalisers is enabled by appropriate electrical filtering.