High-speed optical switching based on diffusive conduction in an optical waveguide with surface-normal optical control

We report a surface-normal optically controlled waveguide switch made of a p-i-n diode that utilizes optically induced voltage screening to turn on and diffusive conduction to turn off. We examine theoretically diffusive conduction in these switches and show that this mechanism offers the possibility of creating optical switches operating at several tens of GHz. As a proof-of-concept demonstration, we present experimental results of wavelength-converting, optical switching at frequencies up to 2.5 GHz in a multiple-quantum-well, GaAs-based waveguide device using milliwatt-level switching powers. Optimized arrays of these devices can be used for high-speed, multichannel wavelength conversion and optical regeneration in wavelength-division-multiplexed systems.