WAVELENGTH-SELECTIVE WAVE-GUIDE PHOTODETECTORS IN SILICON-ON-INSULATOR

We show that silicon-on-insulator substrates, combined with a low inde x waveguide, can yield intrinsically wavelength-selective devices for multiwavelength applications. We demonstrate a simple wavelength-selec tive photodetector that resembles an asymmetric directional coupler wi th a polymer waveguide coupled to a silicon waveguide. Only certain wa velengths are phase-matched between the two guides and transfer from t he polymer to the silicon. Operating the device at the band edge of si licon, the coupled radiation is absorbed and generates photocurrent. T he 400 mu m long detector exhibits a linewidth of a few nm, limited by the uniformity of the silicon-on-insulator material. (C) 1996 America n Institute of Physics.