Low power consumption and continuously tunable all-optical microwave filter based on an opto-mechanical microring resonator

We propose and experimentally demonstrate a continuously tunable all-optical microwave filter using a silicon opto-mechanical microring resonator (MRR). By finely adjusting the pump light with submilliwatt power level, transmission spectrum of the MRR could be continuously shifted based on the nonlinear effects, including the opto-mechanical effect and thermo-optic effect. Therefore, in the case of optical single sideband (OSSB) modulation, the frequency intervals between the optical carrier (near one MRR resonance) and the corresponding resonance could be flexibly manipulated, which is the critical factor to achieve continuously tunable microwave photonic filter (MPF). In the experiment, the central frequency of the MPF could be continuously tuned from 6 GHz to 19 GHz with the pump power lower than -2.5 dBm. The proposed opto-mechanical device is competent to process microwave signals with dominant advantages, such as compact footprint, all-optical control and low power consumption. In the future, using light to control light, the opto-mechanical structure on silicon platforms might have many other potential applications in microwave systems, such as microwave switch.