Various designs of semiconductor lasers may comprise a waveguide having a front region that is configured to support a plurality of transverse laser cavity modes and a rear region that support only one transverse laser cavity mode. These front and rear regions may be disposed between front and rear reflectors and may provide optical gain. Some such designs may be useful for providing higher power single mode semiconductor lasers.

An exemplary embodiment of the invention relates to a method of fabricating a radiation emitter (100) comprising the steps of fabricating a layer stack (10) that comprises a first reflector (12), an active region (13), an oxidizable layer (21-24), and a second reflector (14); and locally removing the layer stack (10), and thereby forming a mesa (M) of the radiation emitter (100), wherein said mesa (M) comprises the first reflector (12), the active region (13), the oxidizable layer (21-24) and the second reflector (14), wherein before or after locally removing the layer stack (10) and forming said mesa (M) the following steps are carried out: vertically etching blind holes (30) inside the layer stack (10), wherein the blind holes (30) vertically extend at least to the oxidizable layer (21-24) and expose the oxidizable layer (21-24); and oxidizing the oxidizable layer (21-24) via the sidewalls (31) of the blind holes (30) in lateral direction, wherein from each hole an oxidation front (32) radially moves outwards and wherein the etching is terminated before the entire oxidizable layer (21-24) is oxidized, thereby forming at least two unoxidized apertures, (40) each of which is limited by at least three oxidation fronts (32), inside the mesa.

A vertical-cavity surface emitting laser includes a substrate, a first reflector, an active region, an oxide layer, a second reflector, and a circular metal electrode. The first reflector is formed above the substrate. The active region is formed above the first reflector, and includes at least one quantum well. The at least one quantum well generates a laser beam with a plurality of modes. The oxide layer is formed above the active region and includes an oxide aperture. The second reflector is formed above the oxide layer. The circular metal electrode is formed in a circular concave in the second reflector. The circular metal electrode reflects other modes of the laser beam with the plurality of modes except for a fundamental mode and receive an operational voltage. A window exists between the circular concave and lets the laser beam with the fundamental mode pass.

A vertical cavity surface emitting laser (VCSEL) device includes an oxide aperture layer positioned in close proximity to the active region of the device, typically within the cavity itself, as opposed to being positioned in the top DBR of the VCSEL. Reducing the spacing between the active region and the oxide aperture layer has been found to reduce the spread of current across the surface of the active region, allowing for a lower threshold current to be achieved. The closer positioning of the oxide aperture layer also reduced optical absorption and series resistance. The oxide aperture layer may be located at the first null in the standing wave pattern between the active region and the top DBR to minimize divergence of the beam and control the optical mode.

A semiconductor laser device of an edge emission type, where a waveguide mode is multi-mode, is provided. The semiconductor laser device includes a first facet of the waveguide on an emission direction front side, the first facet having a first width in a horizontal direction perpendicular to a longitudinal direction of the waveguide; and a second facet of the waveguide on an emission direction rear side, the second facet having the first width, wherein a width of the waveguide, in the horizontal direction, is at least partially narrower than the first width, between the first facet and the second facet.

An optical device is provided that includes a waveguide layer and at least one grating structure. A coupling coefficient of the at least one grating structure to a fundamental optical mode supported by the waveguide layer is greater than a coupling coefficient of the at least one grating structure to at least one higher order transverse optical mode supported by the waveguide layer.

A surface-emitting laser includes a first reflector layer, an active layer provided on the first reflector layer, and a second reflector layer provided on the active layer. The second reflector layer includes a corner reflector that tapers in a direction opposite to the first reflector layer, and the corner reflector has a plan shape of a circle or a polygon with an even number of vertexes.

A semiconductor laser is disclosed. Trim loss region is provided in inner ridge region of surface of transmission layer facing away from substrate, blind hole is provided in trim loss region, and distance from bottom surface of blind hole to surface of second cladding layer facing to substrate is smaller than evanescent wave length in transmission layer. Blind hole can affect optical field characteristics of light transmission in semiconductor laser by affecting evanescent wave. A method for fabricating a semiconductor laser is also provided.

A semiconductor light emitting device of one embodiment of the present disclosure incudes: a GaN substrate having, as a principal plane, a semipolar plane or a non-polar plane inclined from a c-plane in an m-axis direction or an a-axis direction within a range from 20° to 90° both inclusive; an active layer provided on the GaN substrate; and an n-type cladding layer provided between the GaN substrate and the active layer, and including a first layer on the active layer side and a second layer on the substrate side, the first layer including AlGaInN containing 0.5% or more of indium (In), and the second layer being lower in refractive index than the first layer.

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.