Planar lightwave circuit and optical device

Abstract

To provide a planar lightwave circuit capable of being optically connected to a semiconductor optical element or an optical wiring component in a simple, precise, and stable manner without an increase in circuit footprint or the number of fabrication steps or a deterioration of characteristics. By arranging a dummy optical waveguide having a mirror function in the vicinity of an input/output waveguide of an optical functional circuit forming the planar lightwave circuit, a semiconductor optical element or an optical wiring component can be easily aligned with and fixed to the optical functional circuit by monitoring the reflection light intensity from the dummy optical waveguide. When the optical functional circuit has a plurality of input/output waveguides to be optically connected, each input/output waveguide can be identified if the dummy optical waveguides having the mirror function have different reflection properties (such as reflectance, width, position, or reflection wavelength).