Patent ID: 7502402

Claim:
An integrated optical semiconductor device comprising: a semiconductor substrate; a first optical semiconductor element structure including a first laminated structure consisting of one layer or multiple layers, selectively located on the semiconductor substrate, and forming a first heterojunction with the semiconductor substrate, and a second laminated structure consisting of one layer or multiple layers, located on the first laminated structure, and forming a second heterojunction with the first laminated structure, the first laminated structure having a higher etching rate than the etching rate of the semiconductor substrate with respect to a predetermined etchant; a second optical semiconductor element structure having a double heterojunction structure with the same optical axis direction as the first optical semiconductor element structure, having an first end face, orthogonal to the optical axis, on a side facing the first optical semiconductor element structure, located on the semiconductor substrate, and spaced from the first optical semiconductor element structure; an inter-optical semiconductor element structure in contact with the first end face, located on the semiconductor substrate, having the first laminated structure and the second laminated structure, a thickness of 100 μm or less in the optical axis direction, and having an second end face orthogonal to the optical axis on a side facing the first optical semiconductor element structure; and a third optical semiconductor element structure having a double heterojunction structure, in contact with the second end face, located on the semiconductor substrate, and having the same optical axis direction as the first optical semiconductor element structure.