Provided here are: a mesa strip which has an n-type cladding layer, an active layer and a p-type cladding layer that are stacked sequentially on a surface of an n-type substrate; Fe-doped semi-insulating layers which are embedded along both sides of the mesa stripe, each up to a height higher than the mesa stripe; n-type blocking layers which are stacked on respective surfaces of the Fe-doped semi-insulating layers located on the both sides of the mesa stripe, and which are spaced apart from each other with an interval that is a space corresponding to a central portion of the active layer and is thus narrower than the active layer; p-type cladding layers which are formed on back surfaces of respective mesa-stripe-side end portions of the n-type blocking layers; and a p-type cladding layer which buries a top of the mesa stripe, the p-type cladding layers and the n-type blocking layers.

A light emitting device according to an embodiment of the present disclosure includes: a substrate; a first contact layer; a buffer layer in which at least any of a carrier concentration, a material composition, and a composition ratio is different from that of the first contact layer; and a semiconductor stacked body. The substrate has a first surface and a second surface that are opposed to each other. The first contact layer is stacked on the first surface of the substrate. The buffer layer is stacked on the first contact layer. The semiconductor stacked body is stacked above the first surface of the substrate with the first contact layer and the buffer layer interposed in between. The semiconductor stacked body has a light emitting region configured to emit laser light.

An optical device includes: a substrate having a first surface, and a second surface opposite of the first surface; a plurality of surface emitting laser elements provided on the first surface of the substrate and configured to emit light in a direction intersecting the first surface; a plurality of optical elements disposed on the second surface so as to respectively correspond to the plurality of surface emitting laser elements; and an anti-reflection structure between the substrate and the plurality of optical elements.

Provided is a semiconductor laser device including a plurality of semiconductor laser units LDC that are capable of being independently driven, and a spatial light modulator SLM that is optically coupled to a group of the plurality of semiconductor laser units LDC. Each of the semiconductor laser units includes a pair of clad layers having an active layer 4 interposed therebetween, and a diffractive lattice layer 6 that is optically coupled to the active layer 4. The semiconductor laser device includes a ¼ wavelength plate 26 that is disposed between a group of the active layers 4 of the plurality of semiconductor laser units LDC and a reflection film 23, and a polarizing plate 27 that is disposed between the group of the active layers 4 of the plurality of semiconductor laser units LDC and a light emitting surface.

An active layer of a quantum cascade laser includes an active layer includes a plurality of emission regions and a plurality of injection regions. Each emission region includes an injection barrier layer, and an light-emitting quantum well layer that has at least two well layers, and that emits infrared light by undergoing an intersubband transition. Each injection region includes an extraction barrier layer, and a relaxation quantum well layer that creates an energy level for relaxing the energy of carriers from the each emission region. One of adjacent two well layers in the light-emitting quantum well layer of the each emission region on the side of the extraction barrier layer is deeper than a second well layer on the side of the injection barrier layer. The each emission region and the injection region are alternately stacked.

A semiconductor laser element includes: an n-type cladding layer disposed above an n-type semiconductor substrate (a chip-like substrate); an active layer disposed above the n-type cladding layer; and a p-type cladding layer disposed above the active layer, in which the active layer includes a well layer and a barrier layer, an energy band gap of the barrier layer is larger than an energy band gap of the n-type cladding layer, and a refractive index of the barrier layer is higher than a refractive index of the n-type cladding layer.

A semiconductor device. In some embodiments, the semiconductor device includes: a first layer having a first region and a second region, the first region being corrugated with a plurality of corrugations, the second region being uncorrugated. A first cycle of the corrugations may have a first duty cycle and a second cycle of the corrugations may have a second duty cycle, the second cycle being between the first cycle and the second region, and the second duty cycle being between the first duty cycle and the duty cycle of the second region.

A method for fabricating a buried heterostructure semiconductor optical amplifier is provided. The method includes a step providing a patterned dielectric layer on a substrate, the patterned dielectric layer having openings to expose uncovered regions of the substrate. The method also includes, in a single metal organic chemical vapour deposition (MOCVD) run: etching the uncovered regions of the substrate to form angles at corresponding edges thereof and diffusing a p-dopant in the substrate to obtain a p-dopant distribution in a portion of the substrate; etching a portion of the p-dopant thereby defining a recess in the substrate and growing a n-blocking layer in the recess; sequentially growing, over a portion of the n-blocking layer, an active region, a p-overclad, a p-contact, and a p-metal contact; and growing a n-metal contact on a backside of the substrate. The single MOCVD run combines selective area growth, p-dopant diffusion and etching techniques.

A tunable laser that is characterized by including a gain waveguide ACT made of an optically active semiconductor material, and a tunable wavelength filter TWF that selects light of a specific wavelength using current injection, which are integrated on a compound semiconductor substrate S, in which at least one or more of the tunable wavelength filters TWF are formed to select a specific wavelength of light from the light from the waveguide ACT and return the selected specific wavelength of light back to the waveguide ACT, and a semiconductor mixed crystal material constituting the tunable wavelength filter TWF has a strained multiple quantum well structure MQW in which a mixed crystal material ratio changes periodically.

[Object] To provide a vertical cavity surface emitting laser element having a structure whose pitch can be narrowed, a vertical cavity surface emitting laser element array, a vertical cavity surface emitting laser module, and a method of producing a vertical cavity surface emitting laser element.

[Solving Means] A vertical cavity surface emitting laser element according to the present technology includes: a first substrate; and a second substrate. The first substrate is provided with a semiconductor layer including an active layer and a first distributed Bragg reflector (DBR) layer. The second substrate is provided with a constriction layer and a second DBR layer, the constriction layer having a constriction region and an injection region having conductivity higher than that of the constriction region, the second substrate being bonded to the first substrate such that the constriction layer is adjacent to the semiconductor layer.