Fibre nonlinearity mitigation of OOK signals with MLSE utilising MZ filter for diverse VSB filtering

Fibre nonlinearity mitigation of non-return-to-zero on-off keying (NRZ-OOK) signals with diverse-vestigial-sideband (DVSB) filtering maximum likelihood sequence estimation (MLSE) is demonstrated by experiments and simulations, in which DVSB filtering is realised with a Mach-Zehnder (MZ) filter. In a 10.709-Gbit/s NRZ-OOK system, experimental results show that, at a fixed optical signal-to-noise ratio, the Q-factor is improved significantly with DVSB-MLSE compared to that with conventional MLSE. Simulations reveal that the performance of DVSB-MLSE can be further improved by optimising the parameters of DVSB filters for different launch powers.