Optimal bandwidth in optical FSK system influenced by laser phase noise

In this paper, an optical FSK system with TFS (two-filter structure) also known as dual-filter FSK is observed in the presence of laser phase noise. Sensitivity of the receiver is shown as a function of IF bandwidth and a bandwidth of the low-pass postdetection filter. It is shown that there is an optimal pair of bandwidths witch minimizes required receiver sensitivity: a few figures for different amounts of phase noise are given. The results in this paper are based on truncated Taylor expansion method.