Using ${\hbox {SiO}}_{2}$ Carrier Confinement in Total Internal Reflection Optical Switches to Restrict Carrier Diffusion in the Guiding Layer

Total internal reflection optical switches structures are well known. However, previously reported switches based upon carrier injection have suffered from the diffusion of carriers within the guiding layer leading to inefficient reflection. While some attempts have been made to restrict the diffusion of carriers in devices fabricated in materials other than silicon, carrier diffusion has still been possible. In this paper, we propose the use of a thin SiO₂ barrier around the carrier injection region to improve the performance of the device. Modeling data has shown that high-performance switching is possible by confining the carriers in this way. Modeling suggests that switching times of the order of 5 ns can be achieved with a switching current of the order of 30 mA.