Rib waveguide switches with MOS electrooptic control for monolithic integrated optics in GaAs-Al_xGa_1−xAs

Low-loss (1.4-cm(-1)) single-mode rib waveguides in Al(x)Ga(1-x)As heterostructures are fabricated by liquid phase epitaxy, double anodization, and photolithographic techniques. Switching of optical channels between adjacent waveguides is accomplished with directional coupler switches controlled with electrodes laid over an isolating dielectric, making a metal-oxide-semiconductor (MOS) configuration. Complete switching is achieved with <20 V applied to a stepped Deltabetareversal electrode configuration. A 2 x 4 switching matrix with low-loss lateral offsets of the waveguides is demonstrated. By laying out several optical switching and guiding experiments within a 128-mum stripe, we show that independent optical circuits can be packed with adequate optical isolation using centerline separations approximately 10 microm.