A planar optical waveguide is formed with an optical circuit having an inclined groove. A reflection filter is installed on the inside of the inclined groove 3 crossing a plurality of optical waveguides. Reflected light from the reflection filter is detected by an array of photodetectors to monitor the...http://www.google.com/patents/US7149375?utm_source=gb-gplus-sharePatent US7149375 - Optical waveguide module
