Patent ID: 8457452

Claim:
An integrated semiconductor optical device comprising: a semiconductor substrate; a first end facet and second end facet opposite to the first end facet; a first semiconductor optical device including a first lower cladding layer provided on the semiconductor substrate, a first upper cladding layer including a first ridge portion, a first core layer provided between the first lower cladding layer and the first upper cladding layer, a first buried layer surrounding the first ridge portion, and a first adjusting layer provided between the first buried layer and the first ridge portion; and a second semiconductor optical device including a second lower cladding layer provided on the semiconductor substrate, a second upper cladding layer including a second ridge portion, and a second core layer provided between the second lower cladding layer and the second upper cladding layer, wherein the first buried layer contains an insulating material, the first semiconductor optical device and the second semiconductor optical device are arranged next to each other in a predetermined direction, the first core layer is joined to the second core layer by a butt joint method at a joint boundary between the first semiconductor optical device and the second semiconductor optical device, the first adjusting layer has a refractive index lower than a refractive index of the first core layer and higher than a refractive index of the first buried layer, the first adjusting layer extends in the predetermined direction, and the first adjusting layer has a constant width from the first end facet to the joint boundary.