Low threshold optical bistability in a hybrid Si-GaAs cavity with quantum dots.

Optical bistability occurs when an optical system provides two different transmissions for the same input intensity at a steady state, creating a hysteresis. This work presents low threshold optical bistability in a hybrid Si-GaAs photonic crystal cavity with quantum dots where the cavity air holes are only in a silicon waveguide, and the GaAs is a wider slab. Using 3D FDTD, we incorporate a two-level atom system as quantum dots in our cavity to simulate optical bistability. Under the continuous wave excitation at telecom wavelength, we found the bistability threshold is as low as 18.5 µW. This low-power bistability can be promising for various photonic applications like optical logic gates, all-optical switches, and optical transistors.