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 quantum cascade laser having a laser structure that includes a semiconductor mesa, a first end surface, a second end surface, and a first electrode provided on the semiconductor mesa. The laser structure includes a first region having the first end surface and a second region located between the second end surface and the first region. The semiconductor mesa includes a first mesa portion and a second mesa portion that are respectively included in the first region and the second region. The semiconductor mesa includes a first superlattice layer, a second superlattice layer, and a conductive semiconductor region. The first superlattice layer extends from the first end surface in the second axis direction and is included in the first mesa portion and the second mesa portion, and the second superlattice layer is provided in one of the first mesa portion and the second mesa portion.

A method of manufacturing a semiconductor laser element includes: a cleaning process of holding a semiconductor light emission element that emits light from a facet thereof in a plasma sputtering device in which a target is covered with quartz, and cleaning the facet by irradiating the facet with plasma in the plasma sputtering device; and a dielectric film formation process of transporting the cleaned semiconductor light emission element to a deposition device without exposing the semiconductor light emission element to an atmosphere, and forming a dielectric film on the cleaned facet in the deposition device.

A method of manufacturing a semiconductor laser element includes: a cleaning process of holding a semiconductor light emission element that emits light from a facet thereof in a plasma sputtering device in which a target is covered with quartz, and cleaning the facet by irradiating the facet with plasma in the plasma sputtering device; and a dielectric film formation process of transporting the cleaned semiconductor light emission element to a deposition device without exposing the semiconductor light emission element to an atmosphere, and forming a dielectric film on the cleaned facet in the deposition device.

A semiconductor laser (2) includes an n-type semiconductor substrate (1), a stack of an n-type cladding layer (4), an active layer (5), and a p-type cladding layer (6) successively stacked on the n-type semiconductor substrate (1). An optical waveguide (3) includes a non-impurity-doped core layer (9) provided on a light output side of the semiconductor laser (2) on the n-type semiconductor substrate (1) and having a larger forbidden band width than the active layer (5), and a cladding layer (10) provided on the core layer (9) and having a lower carrier concentration than the p-type cladding layer (6). The semiconductor laser (2) includes a carrier injection region (X1), and a non-carrier-injection region (X2) provided between the carrier injection region (X1) and the optical waveguide (3).

A nitride light emitter includes: a nitride semiconductor light-emitting element including an Al.sub.xGa.sub.1-xN substrate (0x1) and a multilayer structure above the Al.sub.xGa.sub.1-xN substrate; and a submount substrate on which the nitride semiconductor light-emitting element is mounted. The multilayer structure includes a first clad layer of a first conductivity type, a first light guide layer, a quantum-well active layer, a second light guide layer, and a second clad layer of a second conductivity type which are stacked sequentially from the Al.sub.xGa.sub.1-xN substrate. The multilayer structure and submount substrate are opposed to each other. The submount substrate comprises diamond. The nitride semiconductor light-emitting element has a concave warp on a surface closer to the Al.sub.xGa.sub.1-xN substrate.

The invention relates to a semiconductor laser (1) comprising a semiconductor layer sequence (2) with an n-type n-region (21), a p-type p-region (23) and an active zone (22) lying between the two for the purpose of generating laser radiation. A p-contact layer (3) that is permeable to the laser radiation and consists of a transparent conductive oxide is located directly on the p-region (23) for the purpose of current input. An electrically-conductive metallic p-contact structure (4) is applied directly to the p-contact layer (3). The p-contact layer (3) is one part of a cover layer, and therefore the laser radiation penetrates as intended into the p-contact layer (3) during operation of the semi-conductor laser (1). Two facets (25) of the semiconductor layer sequence (2) form resonator end surfaces for the laser radiation. Current input into the p-region (23) is inhibited in at least one current protection region (5) directly on at least one of the facets (25). Said current protection region has, in the direction running perpendicularly to the associated facets (25), an extension of at least 0.5 m and at most 100 m, and additionally of at least 20% of a resonator length for the laser radiation.

The invention relates to a semiconductor laser (1) comprising a semiconductor layer sequence (2) with an n-type n-region (21), a p-type p-region (23) and an active zone (22) lying between the two for the purpose of generating laser radiation. A p-contact layer (3) that is permeable to the laser radiation and consists of a transparent conductive oxide is located directly on the p-region (23) for the purpose of current input. An electrically-conductive metallic p-contact structure (4) is applied directly to the p-contact layer (3). The p-contact layer (3) is one part of a cover layer, and therefore the laser radiation penetrates as intended into the p-contact layer (3) during operation of the semi-conductor laser (1). Two facets (25) of the semiconductor layer sequence (2) form resonator end surfaces for the laser radiation. Current input into the p-region (23) is inhibited in at least one current protection region (5) directly on at least one of the facets (25). Said current protection region has, in the direction running perpendicularly to the associated facets (25), an extension of at least 0.5 m and at most 100 m, and additionally of at least 20% of a resonator length for the laser radiation.

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 layeron 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 substratethat 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.

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 layeron 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 substratethat 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.