Low Power and Large Modulation Depth Optical Bistability in an Si Photonic Crystal L3 Cavity

Optical bistability with low power and large modulation depth is observed in the silicon 2D photonic crystal 3 defect-long (L3) cavity coupling with a photonic crystal waveguide experimentally. The cavity-waveguide resonator system operates under the critical coupling condition. The triangular line shape of the cavity resonance and the hysteresis loop of the system is observed. The switching contrast is 7.7 dB and the modulation depth is 0.70 at the switching power of -12.1 dBm. A nonlinear coupled mode model is established to analyze the behavior of the cavity, and numerical simulation results are in good agreement with the experiment results.