Low-Loss, Single-Mode, Optical Phase Modulator in SIMOX Material

Abstract

This paper reports results of the simulation of an optical phase modulator. The proposed modulator consists of an elongated p-i-n structure fabricated in a silicon-on-insulator material such as SIMOX. It utilizes the free-carrier effect to produce the desired refractive index change in a single-mode optical rib waveguide. The MEDICI two-dimensional semiconductor device simulation package has been employed to optimize the overlap between the injected free carriers and the propagating optical guided mode. Although the device is designed to support a single optical guided mode, it measures several micrometers in cross-sectional dimensions, thereby simplifying fabrication and allowing efficient coupling to/from other single-mode devices. Furthermore, the device has an extremely high figure of merit, predicting over 200° of induced phase shift per volt per millimeter, as well as a low drive current of less than 10 mA. This is approximately an order of magnitude lower than most other reported devices in silicon. © 1994 IEEE. All rights reserved.