Phase and amplitude characteristics of a phase-sensitive amplifier operating in gain saturation.

We investigate a non-degenerate phase-sensitive amplifier (PSA) operating in gain saturation experimentally and numerically using the three-wave model. The phase-dependent gain and phase-to-phase transfer functions are obtained for different levels of saturation with good agreement between experimental and numerical data when higher-order FWM is small. Moreover, we identify an operating point where the PSA is found to be able to significantly reduce both phase- and amplitude noise simultaneously.