Low-Power-Consumption Short-Length and High-Modulation-Depth Silicon Electrooptic Modulator

In this paper, we propose and analyze a novel compact electrooptic modulator on a silicon-on-insulator (SOI) rib waveguide. The device confines both optical field and charge carriers in a micron-size region. The optical field is confined by using a planar Fabry–Pérot microcavity with deep Si/SiO2 Bragg reflectors. Carriers are laterally confined in the cavity region by employing deep-etched trenches. The refractive index of the cavity is varied by using the free-carrier dispersion effect produced by a p-i-n diode. The device has been designed and analyzed using electrical and optical simulations. Our calculations predict, for a 20m-long device, a modulation depth of around 80% and a transmittance of 86% at an operating wavelength of 1.55 m by using an electrical power under dc conditions on the order of 25 W.