A Contribution to Study the Effect of Multipath Coherent Crosstalk Due to Optical Network Nodes on DPSK Signals

Multipath coherent crosstalk, due to multiple replicas of the main signal in optical networks, is examined in terms of the potential impact on the performance of optical differential phase-shift keying signals. Analytical expressions are derived and presented for both the moment generating function of the decision variable and the average error probability. A detailed comparison with incoherent crosstalk is also performed. Using symbol-conditioned analysis for this crosstalk, it is shown that for low optical signal-to-noise ratio penalties, the coherent crosstalk is more damaging than the incoherent one.