Abstract

In optical communications, four-wave mixing (FWM) is being explored for all-optical signal processing applications such as wavelength conversion. We previously demonstrated a robust scheme that was transparent to amplitude, phase and polarization of an optical signal, using a single nonlinear semiconductor optical amplifier (SOA) and two pumps with parallel polarizations [1]. We showed that it is possible to achieve polarization insensitive wavelength conversion using a single SOA by setting the detuning between the two pumps (pump-1 and pump-2), lower than that between the pumps and the signal (s), thereby achieving η₁>> η₂, where η₁ and η₂ are the efficiency of the two FWM processes generating the idler frequency at ω_p1 – ω_p2 + ω_s [1]. Here, we show that when the detuning between the two pumps are not significantly lower than that between the pumps, FWM causes polarization dependent loss (PDL), given by, PDL (𝑑𝐵) = 10 log₁₀((𝜂₁+𝜂₂)/𝜂₁).

© 2017 IEEE