A semiconductor laser device includes: a semiconductor laminate body; an insulating layer disposed above the semiconductor laminate body and including a first opening extending in a first direction that is a direction from a front end surface toward a rear end surface; a first electrode disposed above the semiconductor laminate body; a second electrode disposed above the first electrode and the insulating layer; and an adhesion layer disposed between the second electrode and the insulating layer. The adhesion layer includes a second opening that at least partially overlaps with the first opening in plan view, the first electrode is at least partially disposed inside the first opening and the second opening, and the second electrode and the adhesion layer are disposed above the insulating layer between the first opening and at least one of the front end surface or the rear end surface.

In a semiconductor laser device, a semiconductor layer includes a first groove formed on both sides of a ridge, a pair of second recesses facing each other and between which the ridge is interposed on a side of a light emitting surface, and a pair of third grooves in parallel to the first groove from the light emitting surface and interposing the ridge therebetween.

A semiconductor laser device comprises a substrate; a semiconductor layer of a first conductivity type on the substrate; an active layer on the semiconductor layer of the first conductivity type; a semiconductor layer of a second conductivity type on the active layer; a ridge portion in part of the semiconductor layer of the second conductivity type; a dielectric layer covering a region of the semiconductor layer of the second conductivity type other than the ridge portion; a metal layer on the dielectric layer, the metal layer being electrically coupled to the ridge portion; and a conductive member electrically connecting the metal layer to at least the region of the semiconductor layer of the second conductivity type other than the ridge portion.

A semiconductor laser device includes an optical waveguide that extends toward a first end of the semiconductor laser device. The optical waveguide includes a first clad layer, an active layer, a second clad layer, and an electrode layer in this order. A reflecting surface, which has a dielectric film and a metal film in this order from the active layer, crosses the active layer at a second end of the optical waveguide.

A manufacturing method of a nitride-based semiconductor light-emitting element includes: forming an n-type nitride-based semiconductor layer; forming, on the n-type nitride-based semiconductor layer, a light emission layer including a nitride-based semiconductor; forming, on the light emission layer in an atmosphere containing a hydrogen gas, a p-type nitride-based semiconductor layer while doping the p-type nitride-based semiconductor layer with a p-type dopant at a concentration of at least 2.0×10.sup.18 atom/cm.sup.3; and annealing the p-type nitride-based semiconductor layer at a temperature of at least 800 degrees Celsius in an atmosphere not containing hydrogen. In this manufacturing method, a hydrogen concentration of the p-type nitride-based semiconductor layer after the annealing is at most 5.0×10.sup.18 atom/cm.sup.3 and at most 5% of the concentration of the p-type dopant, and a hydrogen concentration of the light emission layer is at most 2.0×10.sup.17 atom/cm.sup.3.

A semiconductor laser includes a semiconductor layer including end faces and at least one of the end faces is configured as a light emission end face. The semiconductor layer includes a waveguide and a light window structure region. The waveguide has a first width and is extended between the end faces. The light window structure region includes an opening having a second width greater than the first width arranged along the waveguide and is formed continuously or intermittently from one to another of the end faces.

A monolithic integrated semiconductor random laser comprising substrate, lower confinement layer on the substrate, active layer on the lower confinement layer, upper confinement layer on the active layer, strip-shaped waveguide layer longitudinally made in middle of the upper confinement layer, P.sup.+ electrode layer divided into two segments and made on the waveguide layer and N.sup.+ electrode layer on a back face of the lower confinement layer, wherein the two segments correspond respectively to gain region and random feedback region. The random feedback region uses a doped waveguide to randomly feedback light emitted by the gain region and then generates random laser which is random in frequency and intensity. Further, the semiconductor laser is light, small, stable in performance and strong in integration.

A distributed feedback (DFB) semiconductor laser device includes an active layer, a first grating layer and a second grating. The first grating layer has a first grating structure with a first grating period. The second grating layer has a second grating structure with a second grating period substantially different from the first grating period. The active layer, the first grating layer and the second grating layer are vertically stacked, and the equivalent grating period of the DFB semiconductor laser device is (2P1P2)/(P1+P2), where P1 and P2 respectively represent the first grating period and the second grating period.

A plasmonic quantum well laser may be provided. The plasmonic quantum well laser includes a plasmonic waveguide and a p-n junction structure extends orthogonally to a direction of plasmon propagation along the plasmonic waveguide. Thereby, the p-n junction is positioned atop a dielectric material having a lower refractive index than material building the p-n junction, and the quantum well laser is electrically actuated. A method for building the plasmonic quantum well laser is also provided.

A semiconductor optical device may include a semiconductor substrate; a mesa stripe structure that extends in a stripe shape in a first direction on the semiconductor substrate and includes a contact layer on a top layer; an adjacent layer on the semiconductor substrate and adjacent to the mesa stripe structure in a second direction orthogonal to the first direction; a passivation film that covers at least a part of the adjacent layer; a resin layer on the passivation film; an electrode that is electrically connected to the contact layer and extends continuously from the contact layer to the resin layer; and an inorganic insulating film that extends continuously from the resin layer to the passivation film under the electrode, is spaced apart from the mesa stripe structure, and is completely interposed between the electrode and the resin layer.