Design of a silicon-based field-effect electro-optic modulator with enhanced light-charge interaction

A new design for an all-silicon field-effect optical modulator in a ring resonator geometry is proposed and modeled by means of finite-element method simulations. It is shown that the optimal relative placement of the ultrathin field-effect-generated charge layers and the optical mode in the strong-confinement waveguides leads to more than an order-of-magnitude enhancement in the light-charge interaction compared with the recent predictions in the literature. We show that such an enhancement could provide optical modulation with a >7 dB extinction-ratio using a voltage swing of only 2 V, thus making our design compatible with complementary metal-oxide semiconductor technology.