Abstract: A semiconductor light receiving element includes a first semiconductor layer, a waveguide type photodiode structure, an optical waveguide structure, and a fourth semiconductor layer. The waveguide type photodiode structure is provided on the first semiconductor layer. The waveguide type photodiode structure includes an optical absorption layer, a second semiconductor layer, a multiplication layer, and a third semiconductor layer. The optical waveguide structure is provided on the first semiconductor layer. The optical waveguide structure includes an optical waveguiding core layer and a cladding layer. An end face of the waveguide type photodiode structure faces to an end face of the optical waveguide structure. The fourth semiconductor layer is located between the end face of the waveguide type photodiode structure and the end face of the optical waveguide structure. The fourth semiconductor layer contacts the multiplication layer at the end face of the waveguide type photodiode structure.

Abstract: A semiconductor light receiving element includes a first semiconductor layer, a waveguide type photodiode structure, an optical waveguide structure, and a fourth semiconductor layer. The waveguide type photodiode structure is provided on the first semiconductor layer. The waveguide type photodiode structure includes an optical absorption layer, a second semiconductor layer, a multiplication layer, and a third semiconductor layer. The optical waveguide structure is provided on the first semiconductor layer. The optical waveguide structure includes an optical waveguiding core layer and a cladding layer. An end face of the waveguide type photodiode structure faces to an end face of the optical waveguide structure. The fourth semiconductor layer is located between the end face of the waveguide type photodiode structure and the end face of the optical waveguide structure. The fourth semiconductor layer is contacted with the multiplication layer of the end face of the waveguide type photodiode structure.

Abstract: An optical semiconductor device comprises a semiconductor substrate, an optical 90-degree hybrid circuit provided on the substrate, a plurality of input optical waveguides provided on the substrate, and a plurality of output optical waveguides provided on the substrate. The plurality of input optical waveguides is optically coupled to input ends of the optical 90-degree hybrid circuit. The plurality of output optical waveguides is optically coupled to output ends of the optical 90-degree hybrid circuit. Each of the plurality of input optical waveguides includes a first curving portion and a first straight portion adjacent to the first curving portion, and each of the plurality of output optical waveguides includes a second curving portion. A central axis of the first curving portion is inwardly offset with respect to a central axis of the first straight portion, and a central axis of the second curving portion follows a raised sine curve.

Abstract: A semiconductor integrated optical device includes: a supporting base including semi-insulating semiconductor; a first photoelectric convertor having first photodiode mesas; a second photoelectric convertor having second photodiode mesas; a first 90° optical hybrid having at least one first multimode waveguide mesa; a second 90° optical hybrid having at least one second multimode waveguide mesa; an optical divider mesa; first and second input waveguide mesas coupling the first and second 90° optical hybrids with the optical divider mesa, respectively; a conductive semiconductor region disposed on the supporting base, the conductive semiconductor region mounting the first photodiode mesas, the second photodiode mesas, the first multimode waveguide mesas, the second multimode waveguide mesas, and the optical divider mesa; a first island semiconductor mesa extending between the first and second multimode waveguide mesas; and a first groove extending through the first island semiconductor mesa and the conductive

Abstract: An optical semiconductor device comprises a semiconductor substrate, an optical 90-degree hybrid circuit provided on the substrate, a plurality of input optical waveguides provided on the substrate, and a plurality of output optical waveguides provided on the substrate. The plurality of input optical waveguides is optically coupled to input ends of the optical 90-degree hybrid circuit. The plurality of output optical waveguides is optically coupled to output ends of the optical 90-degree hybrid circuit. Each of the plurality of input optical waveguides includes a first curving portion and a first straight portion adjacent to the first curving portion, and each of the plurality of output optical waveguides includes a second curving portion. A central axis of the first curving portion is inwardly offset with respect to a central axis of the first straight portion, and a central axis of the second curving portion follows a raised sine curve.

Abstract: A semiconductor integrated optical device includes: a supporting base including semi-insulating semiconductor; a first photoelectric convertor having first photodiode mesas; a second photoelectric convertor having second photodiode mesas; a first 90° optical hybrid having at least one first multimode waveguide mesa; a second 90° optical hybrid having at least one second multimode waveguide mesa; an optical divider mesa; first and second input waveguide mesas coupling the first and second 90° optical hybrids with the optical divider mesa, respectively; a conductive semiconductor region disposed on the supporting base, the conductive semiconductor region mounting the first photodiode mesas, the second photodiode mesas, the first multimode waveguide mesas, the second multimode waveguide mesas, and the optical divider mesa; a first island semiconductor mesa extending between the first and second multimode waveguide mesas; and a first groove extending through the first island semiconductor mesa and the conductive