Patent ID: 7149375

Claim:
An optical waveguide module, comprising: an optical circuit, constituted by a substrate and an optical waveguide formed on said substrate and having a groove formed at a predetermined inclination angle θ(0°<θ) with respect to the vertical axis perpendicular to the optical axis of said optical waveguide so as to cross a predetermined portion of said optical waveguide, a reflection filter that is installed on the inside of said groove of said optical circuit including a portion where signal light transmitted through said optical waveguide passes through, and that reflects part of said signal light according to a specific reflectivity, and a photodetector that detects reflected light of said signal light reflected by said reflection filter, wherein said groove of said optical circuit is formed such that said reflection filter, installed on the inside of said groove, reflects part of said signal light as said reflected light to the top surface side of said optical circuit, and said photodetector is arranged such that said reflected light is made incident onto the light incident face thereof at a predetermined angle Φ, between the light incident face and the light incident direction, within a range of 80°–90°.