All-optical wavelength division multiplexing amplifier based on vacuum induced nonreciprocal bistability in six-wave mixing process with a ring cavity

Abstract

In this article, we experimentally investigate the nonreciprocal bistability (NB) of two six-wave mixing (SWM) processes inside of a ring cavity with a five-level rubidium atomic cell. The degree of NB can be analyzed by the nonreciprocal area (or non-overlapping area) including the frequency offset (in the x-direction) and the intensity difference (in the y-direction) between output states. The frequency offset between the two states of signals is resulting from the Kerr nonlinearity, while the cavity feedback dressing effect determines the intensity difference. Besides, the signals are amplified by the SWM polariton and vacuum induced enhancement. Based on the effect of NB, we study the realization of an all-optical wavelength division multiplexing amplifier (WDMA). The optical contrast and channel equalization radio of this WMDA is contributed from the degree of nonreciprocal area of output states of signals. Such results may have potential applications in all-optical devices and optical communication.