Spurious four-wave mixing in two-pump fiber-optic parametric amplifiers

We present an experimental study on four-wave mixing (FWM) between two signals within a two-pump fiber-optical parametric amplifier (2P-FOPA). We demonstrate that the intensity of FWM spurious tones depend strongly on the signal power and length of the nonlinear medium and present two regimes as a function of the pumps' power. We also compare the amounts of FWM as a function of channel spacing in the 2P-FOPA with or without pumps and show that the presence of parametric gain enhances FWM over a broad spectral range.