Optical modulator having a reflection plate mounted on a reflection end with an inclined angle against the reflection end

摘要

An optical modulator (39) includes a substrate (7) exhibiting an electro-optical Pockels effect and having first and second end surfaces (31, 33) opposite to each other. An optical waveguide (9) of a branched interferometer type is formed on the substrate (7) and has first and second branched waveguide portions (11, 13) with an input end and a reflection side end respectively exposed in the first and second end surfaces (31, 33) of the substrate (7). A modulating electrode (15) is formed on the substrate (7) in a vicinity of the branched interferometer type optical waveguide (9). A reflection plate (35) is mounted on the second end surface (33) of the substrate (7) at an angle of inclination ( theta ) with respect thereto. Still further, a spacer (41) is disposed between a side of the reflection plate (35) and the second end surface (33) of the substrate (7) to thereby define the angle of inclination ( theta ) of the reflection plate (35) with respect to the second end surface (33) of the substrate (7).