We study the nonreciprocal nature of the saturated parametric amplifier response under different pump wavelengths and power levels. The coupled-mode equations are first employed to gain more insight into the origin of directional phase-matched response. We next characterize pump depletion bandwidth and signal induced pump depletion level to identify the optimum pump wavelength and propagation direction. The nonreciprocal behavior was clearly observed at all of the examined pump wavelengths and power levels.