Patent ID: 8873598

Claim:
A waveguide-type optical semiconductor device comprising: a substrate with a main surface; a structure including a stacked semiconductor layer including a core layer provided on the main surface of the substrate, a stripe-shaped mesa portion protruding in a first direction orthogonal to the main surface and extending in a second direction parallel to the main surface, and a pair of stripe-shaped grooves defining the stripe-shaped mesa portion and extending in the second direction; a protrusion portion provided in the pair of stripe-shaped grooves, the protrusion portion including at least one protrusion, the protrusion protruding from the structure in the first direction; and a resin portion covering a side face of the protrusion, the resin portion being buried in the stripe-shaped grooves, wherein the relative position of the protrusion with respect to the structure is fixed, and the side face of the protrusion intersects with the second direction when viewed from the first direction.