Performance evaluation of decision feedback equalizers in fiber communication links

In this paper, the performance of the conventional Decision Feedback (DFE) equalizer as well as the Volterra DFE is investigated in the context of intensity modulated direct detection optical communications links, when non-return to zero on-off keyed (NRZ-OOK) and optical differential encoded phase shift keyed (NRZ-DPSK) transmission is employed. The DFE is used to mitigate either the residual chromatic dispersion resulting from the incomplete optical compensation or the accumulated chromatic dispersion resulting from uncompensated optical transmission. To facilitate realtime implementation, the equalizer structure is dynamically configured discarding coefficients that have a marginal contribution to the performance of the equalizer leading to a significant computational complexity savings.