Inverse-designed all-silicon nanowire array cavities

We designed silicon nanowire array cavities with high optical confinement (Γ) in the central nanowire and a high quality factor (<i>Q</i>) through an inverse design method that maximizes Γ×<i>Q</i>. Moreover, we fabricated an inversely designed cavity with inline input and output waveguides, which is a new configuration for such cavities. The experimental <i>Q</i> exceeded 50,000, which was consistent with a simulation. The cavity exhibited the thermal nonlinearity effect and optical bistability, which indicate that our cavity strongly confines the light in the nanowires.