A photonic crystal surface-emitting laser includes a light emitting region from which light is emitted in a direction crossing an in-plane direction, and a current blocking region that is adjacent to the light emitting region in the in-plane direction and in which current is less likely to flow than in the light emitting region. The light emitting region and the current blocking region each include a photonic crystal layer. The photonic crystal layer has a first region and second regions periodically arranged in the first region. A refractive index of each of the second regions is different from that of the first region. The light emitting region includes a first semiconductor layer, an active layer, and a second semiconductor layer. The first semiconductor layer, the active layer, and the second semiconductor layer are sequentially stacked on top of one another in an emission direction of the light.

In an embodiment, the gain-guided semiconductor laser includes a semiconductor layer sequence and electrical contact pads. The semiconductor layer sequence includes an active zone for radiation generation, a waveguide layer, and a cladding layer. The semiconductor layer sequence further includes a current diaphragm layer which is electrically conductive along a resonator axis (R) in a central region and electrically insulating in adjoining edge regions. Transverse to the resonator axis (R), the central region includes a width of at least 10 ?m and the edge regions includes at least a minimum width. The minimum width is 3 ?m or more. Seen in plan view, the semiconductor layer sequence as well as at least one of the contact pads on the semiconductor layer sequence are continuous components extending in the central region as well as on both sides at least up to the minimum width in the direction transverse to the resonator axis (R) adjoining the central region and beyond the central region.

A semiconductor optical element of the present disclosure includes: a ridge structure provided on a first-conductivity-type semiconductor substrate and including a first-conductivity-type cladding layer and an active layer; a buried structure provided on both side surfaces of the ridge structure; a second-conductivity-type cladding layer and a second-conductivity-type contact layer provided on a surface of the buried structure; a second-conductivity-type ridge upper cladding layer provided above the ridge structure; a recess having a bottom surface formed of an upper surface of the second-conductivity-type ridge upper cladding layer and side surfaces formed of the second-conductivity-type cladding layer and the second-conductivity-type contact layer; a mesa structure having both side surfaces formed by a mesa extending from the second-conductivity-type contact layer to the first-conductivity-type semiconductor substrate.

A hybrid optical assembly includes: a photonic device having a waveguide structure including group IV semiconductor and oxide; and an optical source device including group III-V semiconductor. The source device is bonded to the photonic device. The source device and the waveguide structure are arranged in a direction of a first axis. The source device has a first semiconductor mesa including an upper core layer and a first upper cladding layer and a second semiconductor mesa including a lower core layer and a second upper cladding layer. The first and second semiconductor mesas extend in a direction of a second axis intersecting the first axis. The second semiconductor mesa has a length larger than that of the first semiconductor mesa. The lower core layer, the second upper cladding layer, and the upper core layer and the first upper cladding layer are arranged in the direction of the first axis.

A semiconductor optical device 1 includes an active layer 4 provided on a substrate 2, a clad layer 5 provided on the active layer 4, and a contact layer 7 provided on the clad layer 5. The contact layer 7 contains a first impurity and a second impurity different from the first impurity. A semiconductor light source includes the active layer 4 provided on the substrate 2, the clad layer 5 provided on the active layer 4, and the contact layer 7 provided on the clad layer 5. The contact layer 7 contains the first impurity and the second impurity different from the first impurity.

A group III-nitride semiconductor device comprises a light emitting semiconductor structure comprising a p-type layer and an n-type layer operable as a light emitting diode or laser. On top of the p-type layer there is arranged an n+ or n++-type layer of a group III-nitride, which is transparent to the light emitted from the underlying semiconductor structure and of sufficiently high electrical conductivity to provide lateral spreading of injection current for the light-emitting semiconductor structure.

A semiconductor laser device includes: a first semiconductor layer on a first conductivity side; a second semiconductor layer on the first conductivity side; an active layer; a third semiconductor layer on a second conductivity side different from the first conductivity side; and a fourth semiconductor layer on the second conductivity side. Eg2<Eg3 is satisfied, where Eg2 and Eg3 denote maximum values of band gap energy of the second semiconductor layer and the third semiconductor layer, respectively. The third semiconductor layer includes a first region layer in which band gap energy monotonically decreases toward the fourth semiconductor layer. N2>N3 is satisfied, where N2 denotes an impurity concentration of the second semiconductor layer, and N3 denotes an impurity concentration of the third semiconductor layer.

Embodiments of the present disclosure are directed towards a laser device with a stepped graded index separate confinement heterostructure (SCH), in accordance with some embodiments. One embodiment includes a substrate area, and an active region adjacent to the substrate area. The active region includes an SCH layer, which comprises a first portion and a second portion adjacent to the first portion. A composition of the first portion is graded to provide a first conduction band energy increase over a distance from multiple quantum wells (MQW) to a p-side of a laser device junction. A composition of the second portion is graded to provide a second conduction band energy increase over the MQW to the p-side distance. The first conduction band energy increase is different than the second conduction band energy increase. Other embodiments may be described and/or claimed.

A semiconductor device includes a first pair of nitride semiconductor regions, and a current confinement region which includes a first portion, a second portion disposed on a side of the first portion, and a third portion disposed on another side of the first portion. A width of the second portion is larger than a width of the first portion, the width of the second portion is larger than a width between the first pair of nitride semiconductor regions, and both ends of the second portion are covered by the first pair of nitride semiconductor regions, respectively.

An optical semiconductor device includes a substrate, a semiconductor multilayer which is formed on the substrate, and includes an optical functional layer, an insulating film formed on the semiconductor multilayer, and an electrode formed on a part of the insulating film. The insulating film covers the semiconductor multilayer except for a region in which the semiconductor multilayer and the electrode are electrically connected to each other. At least a part of a region of the insulating film that is overlapped with the electrode is thinner than a region of the insulating film that is not overlapped with the electrode.