Arroyo Optics has developed an add/drop filter for wavelength division multiplexing which is expected to exhibit the following exemplary 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 paves the way for an entirely new class of optical components for high speed WDM networks. In this Phase II program, we propose to develop and fabricate commercially viable add/drop filter prototypes for high speed optical networks based on our proprietary, grating assisted mode coupler technology.