Tunable optical nonreciprocity in double-cavity optomechanical system with nonreciprocal coupling

We propose a double-cavity optomechanical system with nonreciprocal coupling to realize tunable optical nonreciprocity that has the prospect of making an optical device for the manipulation of information processing and communication. Here we investigate the steady-state dynamic processes of the double-cavity system and the transmission of optical waves from opposite cavity directions. The transmission spectrum of the probe field is presented in detail and the physical mechanism of the induced transparency window is analyzed. It is found that the nonreciprocal response of the probe field transmission appears at two different coupling strengths between two cavities, which breaks the spatial symmetry to lead to optical nonreciprocal transmission. In addition, through analytical calculations, we have given the conditions for nonreciprocal effects, and the optimally nonreciprocal effects can be controlled by adjusting both the coupling strengths and the dissipation rates of cavity fields. Due to the simplicity of the device, this study may provide promising opportunities to realize nonreciprocal structures for optical wave transmission.