A surface-emitting laser, which is a ridge waveguide structure, including: a substrate, a first cladding layer, an active layer, a conductive layer, a second cladding layer; the Bragg gratings is etched on the surface of the ridge waveguide; the two upper electrodes are disposed on both sides of the ridge waveguide; two grooves are formed between the ridge waveguide and each of the two upper electrodes; the first waveguide cladding layer includes one or more current confinement regions; or a buried tunnel junction is formed in the second cladding layer for limiting current. The Bragg gratings comprise two first-order gratings and one second-order grating placed between two first-order gratings.

A semiconductor light emitting device includes a substrate, and an array including three or more light emitting elements which are aligned above and along a main surface of a substrate and each emit light. The light emitting elements each include a clad layer of a first conductivity type, an active layer containing In, and a clad layer of a second conductivity type disposed above the substrate sequentially from the substrate. Among the light emitting elements, the compositional ratio of In in the active layer is smaller in the light emitting element located in a central area in an alignment direction than that in the light emitting elements located in both end areas in the alignment direction.

The embodiment relates to a light-emitting device in which a positional relationship between a modified refractive index region's gravity-center position and the associated lattice point differs from a conventional device, and a production method. In this device, a stacked body including a light-emitting portion and a phase modulation layer optically coupled to the light-emitting portion is on a substrate. The phase modulation layer includes a base layer and plural modified refractive index regions in the base layer. Each modified refractive index region's gravity-center position locates on a virtual straight line passing through a corresponding reference lattice point among lattice points of a virtual square lattice on the base layer's design plane. A distance between the reference lattice point and the modified refractive index region's gravity center along the virtual straight line is individually set such that this device outputs light forming an optical image.

The present embodiment relates to a light-emitting device or the like having a structure capable of reducing one power of 1st-order light with respect to the other power. The light-emitting device includes a substrate, a light-emitting portion, and a phase modulation layer including a base layer and a plurality of modified refractive index regions. Each of the plurality of modified refractive index regions has a three-dimensional shape defined by a first surface facing the substrate, a second surface positioned on a side opposite to the substrate with respect to the first surface, and a side surface. In the three-dimensional shape, at least one of the first surface, the second surface, and the side surface has a portion inclined with respect to a main surface.

A vertical cavity surface emitting laser (VCSEL) array may comprise a first subset of VCSELs of a plurality of VCSELs, and a second subset of VCSELs of the plurality of VCSELs. One or more first beams to be emitted by the first subset of VCSELs, when the VCSEL array is powered, and one or more second beams to be emitted by the second subset of VCSELs, when the VCSEL array is powered, may have different patterns of areas of energy intensity. The different patterns of areas of energy intensity may include respective areas of high energy intensity and respective areas of low energy intensity.

A distributed feedback laser, including: a ridge waveguide; two upper electrodes disposed on two sides of the ridge waveguide, respectively; two lower electrodes disposed on two sides of the upper electrodes, respectively; a substrate; a second waveguide cladding layer; an active layer; and a first waveguide cladding layer. The first waveguide cladding layer is n-doped and includes a conductive layer and a refractive layer disposed on the conductive layer. The refractive index of the refractive layer is greater than the refractive index of the active layer. The ridge waveguide includes a ridge region formed by a middle part of the refractive layer. The ridge region includes a surface provided with Bragg gratings. Two grooves are formed between the ridge waveguide and the upper electrodes. The conductive layer is connected to the upper electrodes. The second waveguide cladding layer includes one or more current restricted areas.

A Vertical Cavity Surface Emitting Laser (VCSEL) includes a reflecting surface of the VCSEL. A gain region is positioned on the distributed Bragg reflector that generates optical gain. The gain region comprises a first and second multiple quantum well stack, a tunnel junction positioned between the first and second multiple quantum well stack, and a current aperture positioned on one of the first and second multiple quantum well stack. The current aperture confines a current flow in the gain region. A partially reflective surface and the reflective surface forming a VCSEL resonant cavity, wherein an output optical beam propagates from the partially reflecting surface.

A quantum cascade laser of an embodiment includes a semiconductor stacked body in which a ridge waveguide is provided. The semiconductor stacked body includes an active layer including a quantum well region including a layer including Al; and the active layer emits laser light. The layer that includes Al includes first regions, and a second region interposed between the first regions; the first region includes Al oxide and reaches a prescribed depth inward from an outer edge of the active layer along a direction parallel to a surface of the active layer in a cross section orthogonal to the optical axis; and the second region does not include Al oxide.

Structures for integrated lasers, systems including integrated lasers, and associated fabrication methods. A ring waveguide and a seed region are arranged interior of the ring waveguide. A laser strip extends across a portion of the ring waveguide. The laser strip has an end contacting the seed region and another opposing end. The laser strip includes a laser medium and a p-n junction capable of generating electromagnetic radiation. The p-n junction of the laser strip is aligned with a portion of the ring waveguide.

A distributed feedback laser, including: a ridge waveguide; two upper electrodes disposed on two sides of the ridge waveguide, respectively; two lower electrodes disposed on two sides of the upper electrodes, respectively; a substrate; a second waveguide cladding layer; an active layer; and a first waveguide cladding layer. The first waveguide cladding layer is n-doped and includes a conductive layer and a refractive layer disposed on the conductive layer. The refractive index of the refractive layer is greater than the refractive index of the active layer. The ridge waveguide includes a ridge region formed by a middle part of the refractive layer. The ridge region includes a surface provided with Bragg gratings. Two grooves are formed between the ridge waveguide and the upper electrodes. The conductive layer is connected to the upper electrodes. The second waveguide cladding layer includes one or more current restricted areas.