A method of manufacturing a semiconductor device includes a step of forming a mesa portion including an active layer above a substrate, and an n-type layer above the active layer, a step of forming a current confinement portion on left and right of the mesa portion, the current confinement portion including a p-type current blocking layer, an n-type current blocking layer above the p-type current blocking layer, and an i-type or p-type current blocking layer above the n-type current blocking layer, and a p-type doping step of diffusing p-type impurities into the i-type or p-type current blocking layer, an upper portion of the n-type current blocking layer, and left and right portions of the n-type layer to change the upper portion of the n-type current blocking layer and the left and right portions of the n-type layer to p-type semiconductors.

An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The optical semiconductor device is applied to a ridge-stripe type laser.

A quantum cascade laser integrated device includes: first and second lower semiconductor mesas extending in a direction of a first axis; a covering region disposed on top and side faces of the first and second lower semiconductor mesas, and including a first and second upper semiconductor mesas, the first and second upper semiconductor mesas extending in the direction of the first axis on the first and second lower semiconductor mesas, respectively; and a first and second electrodes disposed on the second upper semiconductor mesa, the first lower semiconductor mesa and the second lower semiconductor mesa each including a quantum cascading core layer, the covering region including a current blocking semiconductor region embedding the first and second lower semiconductor mesas, and a first conductivity-type semiconductor region disposed on the first and second lower semiconductor mesas and the current blocking semiconductor region, and the conductivity-type semiconductor region including an upper cladding region.

A semiconductor laser device having a diffraction grating is disclosed. The semiconductor laser device comprises a first diffraction grating provided on a substrate, a second diffraction grating continuous to one end of the first diffraction grating along an optical waveguide direction, and an active layer provided above the first diffraction grating. The second diffraction grating has a pitch 1.05 times or greater, or 0.95 times or smaller of the pitch of the first diffraction grating.

The present invention provides a semiconductor laser device for improving temperature characteristics of waveguide structures and realizing stable light emitting patterns and high output, and a method for making the same. The semiconductor laser device (1) comprises: an n-type clad layer (5) laminated on a substrate (2); an active layer (6) laminated on the n-type clad layer (5); a p-type clad layer (7) laminated on the active layer (6); and a plurality of waveguide structures (8) formed on the p-type clad layer (7) and having a ridge of a horn shape in top view. In this configuration, a divider (29) is formed between adjacent waveguide structures (8), and the divider (29) comprises: a groove (30) dividing the active layer (6); and a heat dissipation material (34) filled in the groove (30) and having a thermal conductivity higher than a thermal conductivity of a semiconductor layer (4).

An optical element includes a distributed Bragg reflector, wherein the distributed Bragg reflector includes a first-order diffraction grating of a first-order period disposed in a central region, and second-order diffraction gratings of a second-order period having a coupling coefficient smaller than a coupling coefficient of the first-order diffraction grating and disposed in both end regions between which the central region is located.

To provide a semiconductor optical device with device resistance reduced for optical communication. The semiconductor optical device includes an active layer (306) for emitting light through recombination of an electron and a hole; a diffraction grating (309) having a pitch defined in accordance with an output wavelength of the light emitted; a first semiconductor layer (311) including at least Al, made of In and group-V compound, and formed on the diffraction grating; and a second semiconductor layer (307) including Mg, made of In and group-V compound, and formed on the first semiconductor layer (311).

Provided is a butt-jointed (BJ) semiconductor integrated optical device having a high manufacturing yield. A semiconductor integrated optical device, which is configured such that, on a semiconductor substrate, a first semiconductor optical element including an active layer and a second semiconductor optical element including a waveguide layer are butt-jointed to each other with their optical axes being aligned with each other, includes: a semiconductor regrowth layer including at least one of a diffraction grating layer or an etching stop layer, which is formed by one epitaxial growth across an entire surface above the active layer and the waveguide layer; and a cladding layer formed above the semiconductor regrowth layer.

A method for manufacturing a light emitting device can include providing a substrate; forming a first active layer with a first electrical polarity; forming a light emitting region configured to emit light with a target wavelength between 200 nm and 300 nm; forming a second active layer with a second electrical polarity; forming a first electrical contact layer, optionally comprising a first optical reflector; removing a portion of the first electrical contact layer, the second active layer, the light emitting region, and the first active layer to form a plurality of mesas; and forming a second electrical contact layer. Each mesa can include a mesa width smaller than 10 times the target wavelength that confines the emitted light from the light emitting region to fewer than 10 transverse modes, or a mesa width smaller than twice a current spreading length of the light emitting device.

An optical semiconductor device includes: an active region which includes an active layer which produces light when current is injected therein, a first diffraction grating layer having a first diffraction grating with a prescribed grating period, and a phase shift portion formed within the first diffraction grating layer, wherein the phase shift portion provides a phase shift not smaller than 1.5π but not larger than 1.83π; and a distributed reflection mirror region which is optically coupled to a first end of the active region as viewed along a direction of an optical axis, and which includes a second diffraction grating which reflects the light produced by the active region back into the active region.