<title>Application of multiple quantum well Y-junction waveguides for high-speed optical switching</title>

Abstract

We demonstrate all-optical switching in an integrated Y- junction device fabricated using conventional contact photolithography, photo-resist masking and wet chemical etching on a GaAs/AlGaAs multiple quantum well structures. Two different mechanisms that can be used to cause the ultrafast switching are compared. They are the carrier induced nonlinearity and the nonlinearities due to the optical Stark effect. In the first case, the device geometry is exploited by a two-pulse switching process whereby one control pulse turns the device on and a subsequent control pulse turns it off. Here the relatively long relaxation time of the carriers does not impose a limit on the speed of operation and time gating of signal pulses within a 9 ps window was realized in our experiment. In the second case, the nonlinearity is ultrafast and hence switching and recovery takes place during the control pulse evolution. Consecutive switching events spaced 1.7 ps apart has been achieved.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.