Analysis of ultracompact silicon electro-optic modulator based on Cu-insulator-Si hybrid plasmonic donut resonator

We design and analyze an ultracompact silicon electro-optic modulator operating at the 1550-nm wavelengths. The modulator consists of a Cu-insulator-Si hybrid plasmonic donut resonator coupled with a conventional Si channel waveguide. A voltage is applied between the ring-shaped Cu cap and the cylinder Cu contact located at the center-donut to modify the condition of the Cu-insulator-Si capacitor between depletion and accumulation, thus leading to a resonant wavelength shift of the resonator. In a modulator with 1-μm radius and 5-nm HfO₂ gate oxide, numerical simulation predicts an intensity extinction ratio of >;6 dB for a voltage swing of ~3 V, a switching energy of ~50 fJ/bit, and a speed-of-response of >;50 GHz.