Three Cascaded Nano-Mechanical Microring Resonators Enable High-Efficient Optical Diodes

We propose and experimentally demonstrate a passive nano-mechanical optical diode with ultra-high nonreciprocal transmission ratios (NTRs) and low-power consumption based on the significantly enhanced light-matter interaction in three cascaded opto-mechanical microring resonators (MRRs). In the experiment, an ultra-high NTR beyond 50 dB could be achieved with requiring an optical power as low as −3.8 dBm based on the silicon devices for the first time. To the best of our knowledge, it is a record for on-chip passive optical diode by simultaneously considering the NTRs and the power consumption. With dominant advantages of ultra-high NTRs, low-power consumption, compact size and complementary metal-oxide semiconductor (CMOS) compatibility, the energy-efficient nano-mechanical optical diode has extensive applications in on-chip high-efficient optical signal processing.