Abstract: Provided here are: a laser diode section provided on a surface of an n-type InP substrate; a spot-size converter section provided on a surface of the n-type InP substrate, the spot-size converter section being composed of a core layer which causes emitted laser light to propagate therein, a p-type InP cladding layer on a front surface side of the core layer, an n-type InP cladding layer—on a back surface side of the core layer, n-type InP cladding layers provided on the both sides of the core layer, and a p-type InP cladding layer provided on respective surfaces of the p-type InP cladding layer and the first cladding layers; a window region provided on a surface of the n-type InP substrate—that is placed on a front-end side of the core layer; and a monitor PD as a monitor section provided on a surface of the window region.

Abstract: An optical semiconductor device according to the present disclosure includes at least one laser, a plurality of EA modulators to which an output of the laser is connected on an input side and which have absorption peak wavelengths different from each other, a multiplexer to which outputs of the plurality of EA modulators are connected on an input side and to which a waveguide is connected on an output side, a temperature detector configured to detect a temperature of the laser or the plurality of EA modulators and a selection control circuitry configured to switch an EA modulator to operate among the plurality of EA modulators in accordance with a detected temperature of the temperature detector.

Abstract: A semiconductor optical integrated element of the present disclosure includes: a laser diode portion which is provided on one end side above a substrate, has a first optical waveguide, and emits a laser beam; a modulator portion which is provided on another end side, has a second optical waveguide, and modulates the laser beam; a separation region provided between the laser diode portion and the modulator portion; and a pair of grooves provided on both sides along the first optical waveguide and the second optical waveguide. The second optical waveguide in the separation region and the second optical waveguide in a part on the separation region side in the modulator portion have a buried structure, and the second optical waveguide in a remaining part in the modulator portion has a high-mesa-ridge structure.

Abstract: Provided here are: a laser diode section provided on a surface of an n-type InP substrate; a spot-size converter section provided on a surface of the n-type InP substrate, the spot-size converter section being composed of a core layer which causes emitted laser light to propagate therein, a p-type InP cladding layer on a front surface side of the core layer, an n-type InP cladding layer—on a back surface side of the core layer, n-type InP cladding layers provided on the both sides of the core layer, and a p-type InP cladding layer provided on respective surfaces of the p-type InP cladding layer and the first cladding layers; a window region provided on a surface of the n-type InP substrate-that is placed on a front-end side of the core layer; and a monitor PD as a monitor section provided on a surface of the window region.

Abstract: A semiconductor optical integrated device according to the present invention includes a conductive substrate, a laser provided to the conductive substrate, a semi-insulating semiconductor layer provided on the conductive substrate, a photodiode provided on the semi-insulating semiconductor layer and a waveguide that is provided on the conductive substrate and guides output light of the laser to the photodiode, wherein an anode of the photodiode and a cathode of the photodiode are drawn from an upper surface side of the photodiode, and the waveguide and the photodiode are separated from each other by the semi-insulating semiconductor layer.

Abstract: A semiconductor optical integrated device according to the present invention includes a conductive substrate, a laser provided to the conductive substrate, a semi-insulating semiconductor layer provided on the conductive substrate, a photodiode provided on the semi-insulating semiconductor layer and a waveguide that is provided on the conductive substrate and guides output light of the laser to the photodiode, wherein an anode of the photodiode and a cathode of the photodiode are drawn from an upper surface side of the photodiode, and the waveguide and the photodiode are separated from each other by the semi-insulating semiconductor layer.

Abstract: A semiconductor optical element and an optical module in which extinction ratio variation among integrated optical modulation elements is reduced. An optical module has a wavelength multiplexer that multiplexes light respectively emerging from electric-field-absorption modulator (EAM) portions of integrated optical modulation elements, and that outputs the multiplexed light. The integrated optical modulation element has a signal input terminal, a laser element portion, and an EAM portion. Each of the integrated optical modulation elements has a difference between an oscillation wavelength and a barrier layer bandgap wavelength, represented as an LDBG wavelength difference. Variation of the LDBG wavelength differences is limited within a range of ±1 nm.

Abstract: A semiconductor optical element and an optical module in which extinction ratio variation among integrated optical modulation elements is reduced. An optical module has a wavelength multiplexer that multiplexes light respectively emerging from electric-field-absorption modulator (EAM) portions of integrated optical modulation elements, and that outputs the multiplexed light. The integrated optical modulation element has a signal input terminal, a laser element portion, and an EAM portion. Each of the integrated optical modulation elements has a difference between an oscillation wavelength and a barrier layer bandgap wavelength, represented as an LDBG wavelength difference. Variation of the LDBG wavelength differences is limited within a range of ±1 nm.

Abstract: A semiconductor optical element having a mesa structure formed by wet etching, includes a mesa structure having a ridge-type mesa structure or a high-mesa-type mesa structure, the mesa structure being disposed on a semiconductor substrate, and an extended mesa on the semiconductor substrate, the extended mesa being connected to a corner of the mesa structure and being the same material as the mesa structure.

Abstract: A semiconductor optical element having a mesa structure formed by wet etching, includes a mesa structure having a ridge-type mesa structure or a high-mesa-type mesa structure, the mesa structure being disposed on a semiconductor substrate, and an extended mesa on the semiconductor substrate, the extended mesa being connected to a corner of the mesa structure and being the same material as the mesa structure.