Optical manipulation and conversion in whispering gallery mode resonators with pump depletion

Abstract

In this work, we study optical manipulation and conversion in the high-power regime, and thus the unavoidable intrinsic coupling between the pump light and the signal light, i.e. pump depletion, needs to be included. Compared with the transmission properties that are insensitive to the power of the signal light in the low-power regime with pump non-depletion, our results in the high-power regime with pump depletion show that the resonant transmission coefficients of the nonlinearity can be manipulated from 0 to non-zero by adjusting the intensities of the signal light, and thus it behaves as an intensity-dependent all-optical switch. Although the resonant conversion efficiencies from four-wave mixing of the nonlinearity are generally suppressed by power-dependent frequency shifts as a result of self-phase modulation (SPM) and cross-phase modulation (XPM) in the high-pump regime, the conversion efficiencies can be amplified by tuning the frequency detuning of the signal and pump lights. The optical transmission coefficients and conversion efficiencies can also be enhanced by utilizing the interplay between and nonlinearities in the high-pump regime. The mechanism of enhancing the conversion efficiencies to overcome the suppression from SPM and XPM provides a new way to convert frequency with high efficiencies.