Semiconductor optical device and method for manufacturing the same

A method for manufacturing a semiconductor optical device, the method comprising:

• a step of physically connecting a semiconductor layer to an upper surface of a substrate so as to overlap and connect to a portion of a waveguide made of silicon, the upper surface includes the waveguide, the semiconductor layer including a diffraction grating formed of a first semiconductor layer and a second semiconductor layer having different refractive indices,
• wherein the waveguide includes a bent portion and a plurality of straight portions that are connected to each other by the bent portion and that extend straight,
• wherein the first semiconductor layer and the second semiconductor layer are each made of a compound semiconductor,
• wherein the second semiconductor layer is embedded in the first semiconductor layer and includes a plurality of portions arranged in a direction in which the plurality of straight portions extend, and
• wherein, in the step of joining the semiconductor layer to the substrate, the semiconductor layer is joined so that the diffraction grating extends in the direction in which the plurality of straight portions extend and is positioned above the plurality of straight portions.