Silicon optical diode based on cascaded photonic crystal cavities.

An all-silicon passive optical diode based on optical nonlinearity in cascaded photonic crystal (PhC) L3 cavities is proposed and demonstrated. A nonreciprocal transmission ratio (NTR) of 30.8 dB and insertion loss of 8.3 dB are realized in the device. The device has a relatively broad 17 dB operation bandwidth of 0.08 nm, and at least 16 dB of NTR is achieved when input power varies between -6.25   and -2.95  dBm. A nonlinear couple mode model for cascaded PhC cavities is established to analyze the behavior of the device, and numerical simulation results are in good agreement with the experiment results.