A front facet of the semiconductor laser device includes a resonator facet portion containing an end of an active layer, and a protruding portion which protrudes beyond the resonator facet portion in a resonator length direction by a predetermined protrusion amount and has a stepped bottom surface portion. The resonator facet portion and the stepped bottom surface portion are connected to each other to form a corner portion. The distance from a thickness center position of the active layer to the stepped bottom surface portion is defined by a bottom surface portion depth. The bottom surface portion depth is set to be equal to a predetermined specific depth or deeper than the specific depth.

A QCL may include a substrate, and a semiconductor layer adjacent the substrate. The semiconductor layer may define branch active regions, and a stem region coupled to output ends of the branch active regions. Each branch active region may have a number of stages less than 30.

The invention relates to an edge-emitting semiconductor laser diode, having: —a semiconductor layer sequence, which comprises a bottom surface, a ridge waveguide on a top surface facing away from the bottom surface, and a side surface which is arranged transverse to the top surface, and —a first recess, which extends from the bottom surface to the top surface, wherein —a first region of the semiconductor layer sequence is removed from the side surface in the region of the first recess. The invention further relates to a method for producing a plurality of edge-emitting semiconductor laser diodes.

A laser includes a distributed Bragg minor and is configured to emit monochromatic light radiation along a longitudinal direction. The laser has layers, stacked along a first transverse direction normal to the longitudinal direction and made of III-V materials, including an active region configured to emit the radiation. The mirror is formed by periodic lateral corrugations which extend mainly along the longitudinal direction and having a dimension along a second transverse direction normal to the longitudinal direction. The lateral corrugations of the Bragg minor extend from a top surface of the waveguide pattern along the first transverse direction on a height strictly less than the depth, at which the active region is located starting from the top surface, such that a portion of lateral flanks of the waveguide is free of any lateral corrugations at the active region.

A laser is provided, including: a distributed Bragg mirror; a waveguide, the laser to emit light radiation along a longitudinal direction x, and the waveguide formed at least in part in a stack of layers made of III-V materials including at least one active region to emit the light radiation, the mirror including lateral corrugations distributed periodically along the direction x in a period Λ, the corrugations being carried by at least a lateral plane xz defined by the direction x and a first transverse direction z normal to the direction x, the corrugations having a dimension d along a second transverse direction y normal to the direction x; and a top electrode arranged on the waveguide along the direction z, the corrugations being partly located at lateral flanks of the top electrode, extending parallel to the plane xz, and extending only on the lateral flanks of the top electrode.

A semiconductor laser device includes a laser resonator including a layered structure in which a lower cladding layer, an active layer, and an upper cladding layer are formed over a semiconductor substrate, and a ridge that is formed on the upper cladding layer. The laser resonator emits laser light having a beam profile. When viewed in plan from a direction orthogonal to the semiconductor substrate, the laser resonator has an emission area on its emission end face. When the emission end face of the laser resonator is viewed in front, a virtual line defined by the intensity being 1/e.sub.2 of the peak intensity of the beam profile of the laser light fits inside the upper cladding layer in the emission area.

A semiconductor optical device includes a first facet bounding a first end of the semiconductor optical device. The semiconductor optical device further includes a waveguide having a first end proximate the first facet, the first end of the waveguide being tapered towards the first facet. The first facet has a curvature to increase modal reflectivity at a first interface at which the first end of the waveguide meets the first facet.

Techniques for efficient alignment of a semiconductor laser in a Photonic Integrated Circuit (PIC) are disclosed. In some embodiments, a photonic integrated circuit (PIC) may include a semiconductor laser that includes a laser mating surface, and a substrate that includes a substrate mating surface. A shape of the laser mating surface and a shape of the substrate mating surface may be configured to align the semiconductor laser with the substrate in three dimensions.

An optical device has a gallium and nitrogen containing substrate including a surface region and a strain control region, the strain control region being configured to maintain a quantum well region within a predetermined strain state. The device also has a plurality of quantum well regions overlying the strain control region.

A gallium and nitrogen containing laser diode device. The device has a gallium and nitrogen containing substrate material comprising a surface region. The surface region is configured on either a non-polar crystal orientation or a semi-polar crystal orientation. The device has a recessed region formed within a second region of the substrate material, the second region being between a first region and a third region. The recessed region is configured to block a plurality of defects from migrating from the first region to the third region. The device has an epitaxially formed gallium and nitrogen containing region formed overlying the third region. The epitaxially formed gallium and nitrogen containing region is substantially free from defects migrating from the first region and an active region formed overlying the third region.