Arroyo Optics has developed an add/drop filter for wavelength division multiplexing that is expected to exhibit the following exemplary performance characteristics: high routing efficiency (99%), zero loss (<0.1 dB), high rejection (<-50 dB), narrow bandwidth (1 nm) and low crosstalk (<-30 dB). This device enables an entirely new class of optical components to be developed for high speed WDM networks. In this Phase II program, we propose to fabricate narrowband, wavelength selective optical switches for high speed WDM networks based on our proprietary, grating assisted mode coupler technology.