High-order sideband generation in a two-cavity optomechanical system with modulated photon-hopping interaction

The high-order sideband generation in a two-cavity optomechanical system is discussed, where photon hopping between the two cavity modes is modulated sinusoidally. We show that the high-order sideband generation can be induced originating from two processes: the parametric frequency conversion between the photon-photon interactions and the nonlinear optomechanical interactions between the photon-phonon interactions. Both the modulation amplitude and frequency of photon hopping between the two cavities have flexible manipulation on the high-order sideband generation at the low pump power level. With the modulation amplitude varying, we are able to obtain a robust comb-type spectral structure and a weak spectral structure, which can be amplified by tuning the modulation frequency. Selective generation of particular sidebands may also been achieved via transforming the modulation frequency when the parametric conversion process is dominant. Moreover, the dependence of the high-order sideband generation on other important parameters is also discussed in detail, including the cavities linewidthes, the frequency detuning of the two input laser fields and the intensity of control field. These results may provide further insights into the understanding of the high-order sideband generation, and find applications in optical frequency converters and optical frequency combs.