Nonvolatile silicon photonic switch with graphene based flash-memory cell

Abstract

A nonvolatile silicon photonic switch constructed by a hybrid integration of a back-gate flash-memory unit with a silicon waveguide is proposed. It can persistently maintain the switching state without continuous supplies due to the memory function of the flash unit, which makes it attractive to reduce the static power consumption. The single-gate control configuration is replaced by dual electrodes (back-gate and drain electrodes) to break the symmetrical electric field and ensure the success of the programming/erasing process. Additionally, a monolayer graphene is utilized instead of polysilicon as the floating gate of flash unit to alleviate the bandwidth-extinction ratio restriction with low insertion loss. Depending on appropriate voltage stimulus, the device either acts as an intensity switch or a phase switch. 26.7μm length is able to achieve 20dB extinction ratio, 1.4dB insertion loss and almost no phase change in a non-resonant configuration, which allows truly broadband performance; while a π-shift is achieved by 30μm length with 31dB/1.65dB extinction ratio/insertion loss incorporating into arms of a Mach-Zehnder interferometer.