In a semiconductor laser according to an embodiment of the present disclosure, a ridge part has a structure in which a plurality of gain regions and a plurality of Q-switch regions are each disposed alternately with each of separation regions being interposed therebetween in an extending direction of the ridge part. The separation regions each have a separation groove that separates from each other, by a space, the gain region and the Q-switch region adjacent to each other. The separation groove has a bottom surface at a position, in a second semiconductor layer, higher than a part corresponding to a foot of each of both sides of the ridge part.

This disclosure describes a red-green-blue (RGB) vertical-cavity surface-emitting laser (VCSEL) array. Each VCSEL in the VCSEL array has a grating, one or more active regions and two distributed Bragg reflectors. Each VCSEL corresponds to either red, green or blue wavelengths. The number of active regions in each VCSEL may be based on the color emitted.

A laser source for use in a structured light projector includes a substrate, one or more first VCSELs on the substrate, and one or more second VCSELs on the substrate. The one or more first VCSELs each have a first aperture width and each separately extend above a surface of the substrate. The one or more second VCSELs each have a second aperture width different from the first aperture width, and each separately extend above a surface of the substrate. Using an array of VCSELs with different aperture widths provides emitted radiation having different wavelengths, thus providing different speckle patterns. When the different speckle patterns are averaged upon being received at the detector, speckle noise is reduced. The VCSEL can also include a plurality of subwavelength structures to steer the light output. Such subwavelength structures can also be used on the surface of other VCSELs, including standard VCSELs.

A semiconductor laser comprising a single mode laser cavity having a stack of semiconducting layers defining a transversal p-n junction is provided. A plurality of electrodes are coupled to corresponding sections of the laser cavity along the longitudinal light propagation direction, each corresponding section defining one of an amplification section or a modulation section. One or more DC sources are coupled to the electrodes associated with the amplification sections to forward-bias the p-n junction above transparency, so as to provide gain in the associated amplification sections. One or more modulation signal sources are coupled to the electrodes associated with the modulation sections, and apply a modulation signal across the p-n junction below transparency, the modulation signal providing a modulation of an output optical frequency of the semiconductor laser. Each modulation section is operated in photovoltaic mode.

A method for making a laser diode with a distributed grating reflector (RT) in a planar section of a semiconductor laser with stabilized wavelength includes providing a diode formed by a substrate (S), a first cladding layer (CL1) arranged on the substrate (S), an active layer (A) arranged on the first cladding layer (CL1) and adapted to emit a radiation, and a second cladding layer (CL2) arranged on the active layer (A), said cladding layers (CL1, CL2) being adapted to form a heterojunction to allow for efficient injection of current into the active layer (A) and optical confinement, and a contact layer. The manufacturing method provides for creating, on a first portion (ZA) of the device, a waveguide (GO) for confinement of the optical radiation and, on the remaining portion (ZP) of the device, two different gratings for light reflection and confinement. The two gratings define two different zones (R1, R2), wherein the first zone (R1) includes a grating of low order and high duty cycle, and is intended for reflection, and the second zone (R2) includes a grating of the same order, or a grating of a higher order than the previous one, and low duty cycle, and is mainly intended for light confinement. The waveguide (GO) for confining the optical radiation is implemented through a lithography and a subsequent etching, whereas the grating (RT) requires a high-resolution lithography and a shallow etching starting from a planar zone.

A light emitting device includes a substrate, a buffer layer, a first active layer, and a plurality of mesa regions. A portion of the first active layer includes a first electrical polarity. The plurality of mesa regions includes at least a portion of the first active layer, a light emitting region on the portion of the first active layer, and a second active layer on the light emitting region. A portion of the second active layer includes a second electrical polarity. The light emitting region is configured to emit light which has a target wavelength between 200 nm to 300 nm. A thickness of the light emitting region is a multiple of the target wavelength, and a dimension of the light emitting region parallel to the thickness is smaller than 10 times the target wavelength, such that the emitted light is confined to fewer than 10 transverse modes.

A semiconductor laser includes an active region, a first distributed-Bragg-reflector region disposed contiguously with the active region, and a second distributed-Bragg-reflector region. The first distributed-Bragg-reflector region is formed contiguously with one side of the active region in a waveguide direction and includes a first diffraction grating. The second distributed-Bragg-reflector region is formed contiguously with to the other side of the active region in the waveguide direction and includes a second diffraction grating. The first diffraction grating includes recessed portions formed through a diffraction grating layer formed in the first distributed-Bragg-reflector region and convex portions adjacent to the recessed portions. The diffraction grating layer is made of a dielectric material.

An interband cascade laser including: a ridge waveguide having alternating first and second regions; wherein the first region has a constant width, and the second region has a width that matches that of the first region at boundaries between the first region and the second region, and the width of the second region increases to a maximum that is larger than the width of the first region, such that a partially-corrugated sidewall along each side of the ridge waveguide is formed; wherein the first region comprises a grating structure, and due to periodic nature of the first region, the grating structure is in a form of a sampled grating; and wherein the partially-corrugated sidewall increases waveguide losses for radiation in higher order lateral modes as compared to the fundamental waveguide mode.

A broad area quantum cascade laser subject to having high order transverse optical modes during operation includes a laser cavity at least partially enclosed by walls, and a perturbation in the laser cavity extending from one or more of the walls. The perturbation may have a shape and a size sufficient to suppress high order transverse optical modes during operation of the broad area quantum cascade laser, whereby a fundamental transverse optical mode is selected over the high order transverse optical modes. As a result, the fundamental transverse mode operation in broad-area quantum cascade lasers can be regained, when it could not otherwise be without such a perturbation.

A semiconductor laser comprising a single mode laser cavity having a stack of semiconducting layers defining a transversal p-n junction is provided. A plurality of electrodes are coupled to corresponding sections of the laser cavity along the longitudinal light propagation direction, each corresponding section defining one of an amplification section or a modulation section. One or more DC sources are coupled to the electrodes associated with the amplification sections to forward-bias the p-n junction above transparency, so as to provide gain in the associated amplification sections. One or more modulation signal sources are coupled to the electrodes associated with the modulation sections, and apply a modulation signal across the p-n junction below transparency, the modulation signal providing a modulation of an output optical frequency of the semiconductor laser. Each modulation section is operated in photovoltaic mode.