A semiconductor laser device includes a first cladding including gallium nitride (GaN) on a substrate, a light waveguide on the first cladding, a first contact pattern, a first SCH pattern, a first active pattern, a second SCH pattern, a second cladding and a second contact pattern sequentially stacked on the light waveguide, and first and second electrodes on the first and second contact patterns, respectively.

An AlGaInPAs-based semiconductor laser device includes a substrate, an n-type clad layer, an n-type guide layer, an active layer, a p-type guide layer composed of AlGaInP containing Mg as a dopant, a p-type clad layer composed of AlInP containing Mg as a dopant, and a p-type cap layer composed of GaAs. Further, the semiconductor laser device has, between the p-type guide layer and the p-type clad layer, a Mg-atomic concentration peak which suppresses inflow of electrons, moving from the n-type clad layer to the active layer, into the p-type guide layer or the p-type clad layer.

A semiconductor laser element includes: a first conductivity-type cladding layer; a first guide layer disposed above the first conductivity-type cladding layer; an active layer disposed above the first guide layer; and a second conductivity-type cladding layer disposed above the active layer. A window region is formed in a region of the active layer including part of at least one of the front-side end face or the rear-side end face, the first conductivity-type cladding layer consists of (Al.sub.xGa.sub.1-x).sub.0.5In.sub.0.5P, the first guide layer consists of (Al.sub.yGa.sub.1-y).sub.0.5In.sub.0.5P, and the second conductivity-type cladding layer consists of (Al.sub.zGa.sub.1-z).sub.0.5In.sub.0.5P, where x, y, and z each denote an Al composition ratio, 0<x−y<z−y is satisfied, and D/L>0.03 is satisfied, where L denotes a length of the resonator and D denotes a length of the window region in the first direction.

A nitride semiconductor laser device of one embodiment of the present disclosure includes a single-crystal substrate, a base layer, a sheet-shaped structure, a light emitting layer, and a resonator mirror. The single-crystal substrate extends in one direction. The base layer is provided on the single-crystal substrate and includes a nitride semiconductor. The sheet-shaped structure is provided on the base layer to stand in a direction perpendicular to the base layer. The sheet-shaped structure has an area of a side surface that is greater than an area of an upper surface. The side surface extends in a longitudinal direction of the single-crystal substrate. The sheet-shaped structure includes a nitride semiconductor. The light emitting layer is provided at least on the side surface of the sheet-shaped structure. The light emitting layer includes a nitride semiconductor. The resonator mirror is provided by a pair of end surfaces of the sheet-shaped structure that oppose each other in the longitudinal direction.

An optical semiconductor device of the present disclosure comprises: a ridge structure formed on a first-conductivity-type semiconductor substrate; a buried layer buried on both side surfaces of the ridge structure; a second-conductivity-type second cladding layer and a second-conductivity-type contact layer laminated on the top of the ridge structure and the surface of the buried layer; a stripe-shaped mesa structure formed of a mesa reaching from the second-conductivity-type contact layer to the first-conductivity-type semiconductor substrate; a heat dissipation layer formed on the surface of the second-conductivity-type contact layer; a mesa protective film covering both side surfaces of the mesa structure and both end portions of the surface of the second-conductivity-type contact layer; and a second-conductivity-type-side electrode electrically connected to the second-conductivity-type contact layer.

An apparatus is configured to operate in a single fundamental transverse mode and the apparatus includes a waveguide layer between an n-doped cladding layer and a p-doped cladding layer. The waveguide layer includes a first waveguide part, and an active layer located between the first waveguide part and the p-doped cladding layer, the active layer being asymmetrically within the waveguide layer closer to the p-doped cladding layer than the n-doped cladding layer. The refractive index of the n-doped cladding layer being equal to or larger than the p-doped cladding layer. A first end of the first waveguide part is adjacent to the n-doped cladding layer. A second end of the first waveguide part is adjacent to a first end of the active layer. A desired donor density is doped in the first waveguide part for controlling the carrier density dependent internal optical loss in the first waveguide part at high injection levels.

A portable lighting apparatus is provided with a gallium-and-nitrogen containing laser diode based white light source combined with an infrared illumination source which are driven by drivers disposed in a printed circuit board assembly enclosed in a compact housing and powered by a portable power supply therein. The portable lighting apparatus includes a first wavelength converter configured to output a white-color emission and an infrared emission. A beam shaper may be configured to direct the white-color emission and the infrared emission to a front aperture of a compact housing of the portable lighting apparatus. An optical transmitting unit is configured to project or transmit a directional light beam of the white light emission and/or the infrared emission for illuminating a target of interest, transmitting a pulsed sensing signal or modulated data signal generated by the drivers therein. In some configurations, detectors are included for depth sensing and visible/infrared light communications.

A nitride-based semiconductor light-emitting element includes a semiconductor stack body that includes: an N-type first cladding layer; an N-side guide layer; an active layer that includes a well layer and a barrier layer; a P-side guide layer; and a P-type cladding layer. Band gap energy of the P-side guide layer monotonically increases with an increase in distance from the active layer. An average of the band gap energy of the P-side guide layer is greater than or equal to an average of band gap energy of the N-side guide layer. Band gap energy of the barrier layer is less than or equal to a smallest value of the band gap energy of the N-side guide layer and a smallest value of the band gap energy of the P-side guide layer. A thickness of the P-side guide layer is greater than a thickness of the N-side guide layer.

Embodiments of the invention describe apparatuses, optical systems, and methods related to utilizing optical cladding layers. According to one embodiment, a hybrid optical device includes a silicon semiconductor layer and a III-V semiconductor layer having an overlapping region, wherein a majority of a field of an optical mode in the overlapping region is to be contained in the III-V semiconductor layer. A cladding region between the silicon semiconductor layer and the III-V semiconductor layer has a spatial property to substantially confine the optical mode to the III-V semiconductor layer and enable heat dissipation through the silicon semiconductor layer.

A semiconductor laser device lases in a multiple transverse mode and includes a stacked structure where a first conductivity-side semiconductor layer, an active layer, and a second conductivity-side semiconductor layer are stacked above a substrate. The second conductivity-side semiconductor layer includes a current block layer having an opening that delimits a current injection region. Side faces as a pair are formed in portions of the stacked structure that range from part of the first conductivity-side semiconductor layer to the second conductivity-side semiconductor layer. The active layer has a second width greater than a first width of the opening. The side faces in at least part of the first conductivity-side semiconductor layer are inclined to the substrate. A maximum intensity position in a light distribution of light guided in the stacked structure, in a direction of the normal to the substrate, is within the first conductivity-side semiconductor layer.