Abstract

We demonstrate the simultaneous, independent, and nearly identical operation on nanosecond time scales of GaAs optical bistable devices. A Wollaston prism inserted into the input beam produced two equal-intensity beams which were focused to <10-μm diam spots centered ~40 μm apart. Achievement of equal switch-on intensities for the two spots was straightforward and easy. Elimination of either beam by a polarizer revealed no visible change in the response to the other; thus the switches operated independently. Operation of four spots did not yield uniform response in this initial attempt. The device consists of sixty-one periods of 299 Å GaAs and 98 Å AIGaAs multiple quantum well structure capped by ~2000-Å AI­GaAs windows and sandwiched between 94% reflectance mirrors. Using two independently controlled beams we could vary continuously the distance between two spots. Diffusive crosstalk was then identified by a decrease in switch-on intensity of one of the beams when the other beam was brought sufficiently close. The extent of the carrier diffusion varied with position on the sample, orientation of the spots, and the switch-on intensities. The critical spacing at which crosstalk became noticeable ranged from 35 μm to more than 100 μm.

© 1985 Optical Society of America