A semiconductor laser element includes: a resonator structure including a stacked structure in which a first compound semiconductor layer, an active layer, and a second compound semiconductor layer are stacked; and a first light reflective layer and a second light reflective layer which are provided at both ends along a resonance direction of the resonator structure. When an oscillation wavelength is set to λ, each of the first light reflective layer and the second light reflective layer includes a refractive index periodic structure including, in a stacked manner, a plurality of thin films each having an optical film thickness of k0 (λ/4). A phase shift layer is provided inside at least one light reflective layer of the first light reflective layer or the second light reflective layer.

An optically pumped tunable VCSEL swept source module has a VCSEL and a pump, which produces light to pump the VSCEL, wherein the pump is geometrically isolated from the VCSEL. In different embodiments, the pump is geometrically isolated by defocusing light from the pump in front of the VCSEL, behind the VCSEL, and/or by coupling the light from the pump at an angle with respect to the VCSEL. In the last case, angle is usually less than 88 degrees. There are further strategies for attacking pump noise problems. Pump feedback can be reduced through (1) Faraday isolation and (2) geometric isolation. Single frequency pump lasers (Distributed feedback lasers (DFB), distributed Bragg reflector lasers (DBR), Fabry-Perot (FP) lasers, discrete mode lasers, volume Bragg grating (VBG) stabilized lasers can eliminate wavelength jitter and amplitude noise that accompanies mode hopping.

A multi-junction VCSEL is formed by as a compact structure that reduces lateral current spreading by reducing the spacing between adjacent active regions in the stack of such regions used to from the multi-junction device. At least two of the active regions within the stack are located adjacent peaks of the intensity profile of the VCSEL, with an intervening tunnel junction positioned at a trough between the two peaks. The alignment of the active regions with the peaks maximizes the generated optical power, while the alignment of the tunnel junction with the trough minimizes optical loss. The close spacing on adjacent peaks forms a compact structure (which may even include a cavity having a sub-λ optical length) that lessens the total path traveled by carriers and therefore reduces lateral current spread.

A light emitting element of the present disclosure includes a compound semiconductor substrate 11, a stacked structure 20 including a GaN-based compound semiconductor, a first light reflection layer 41, and a second light reflection layer 42. The stacked structure 20 includes, in a stacked state a first compound semiconductor layer 21, an active layer 23, and a second compound semiconductor layer 22. The first light reflection layer 41 is disposed on the compound semiconductor substrate 11 and has a concave mirror section 43. The second light reflection layer 42 is disposed on a second surface side of the second compound semiconductor layer 22 and has a flat shape. The compound semiconductor substrate 11 includes a low impurity concentration compound semiconductor substrate or a semi-insulating compound semiconductor substrate.

Resonant optical cavity light emitting devices are disclosed, where the device includes a substrate, a first spacer region, a light emitting region, a second spacer region, and a reflector. The light emitting region is configured to emit a target emission deep ultraviolet wavelength and is positioned at a separation distance from the reflector. The reflector may be a distributed Bragg reflector. The device has an optical cavity comprising the first spacer region, the second spacer region and the light emitting region, where the optical cavity has a total thickness less than or equal to K.Math.λ/n. K is a constant ranging from 0.25 to 10, λ is the target wavelength, and n is an effective refractive index of the optical cavity at the target wavelength.

A VCSEL can include: a substrate that passes light therethrough; a phase matching layer over a top mirror stack; a first metal layer over the phase matching layer; and an end metal region over the first metal layer. The phase matching layer and first metal layer have a cooperative thickness to provide reflectivity of at least a predetermined reflectivity threshold for the emission wavelength. A method of making a VCSEL can include: providing a substrate; forming a first mirror stack above the substrate; forming an active region above the first mirror stack; and forming a reflective end above the active region, the reflective end having a phase matching layer and a first metal layer. The phase matching layer and first metal layer have a combined thickness for the reflective end to have a reflectivity of at least a predetermined reflectivity threshold for an emission wavelength of the VCSEL.

A Vertical Cavity Surface Emitting Laser (VCSEL) has a mesa having an active region, which has m active layer structures (with m≥2). The active layer structures are electrically connected to each other by a tunnel junction therebetween. The mesa has an optical resonator, which has first and second DBRs. The active region is between the first and second DBRs. The VCSEL has first and second electrical contacts, which provide electrical current to the active region, and an electrical control contact, which controls gain-switched laser emission of the VCSEL by at least 1 up to m−1 active layer structures by a current between the electrical control contact and the first or second electrical contact. A current aperture is between the active region and the first or second electrode. A distance between the current aperture and a furthest active layer structure is at least three times the laser light's wavelength.

Some embodiments relate to a method for forming a vertical cavity surface emitting laser (VCSEL) structure. The method includes forming an optically active layer over a lower reflective layer and forming an upper reflector over the optically active layer. A first spacer is formed along sidewalls of the upper reflector. An oxidation process is performed with the first spacer in place to oxidize a peripheral region of the optically active layer. A first etch process is performed on the lower reflective layer and the oxidized peripheral region, thereby forming a lower reflector and an optically active region.

An optoelectronic device includes a carrier substrate and a lower distributed Bragg-reflector (DBR) stack disposed on an area of the substrate and including alternating first layers. A set of epitaxial layers disposed over the lower DBR includes a quantum well structure. An upper DBR stack disposed over the set of epitaxial layers includes alternating second layers. Electrodes apply an excitation current to the quantum well structure. At least one of the electrodes includes a metal ring disposed at an inner side of at least one of the DBR stacks in proximity to the quantum well structure. One or more metal vias pass through the at least one of the DBR stacks so as to connect the metal ring at the inner side of the at least one of the DBR stacks to an electrical contact on an outer side of the at least one of the DBR stacks.

A method of manufacturing a light emitting element includes, at least: (A) forming a stacked structure 20 which includes a GaN-based compound semiconductor and in which a first compound semiconductor layer 21, an active layer 23, and a second compound semiconductor layer 22 are stacked, and forming a concave mirror section 43 on a first surface side of the first compound semiconductor layer 21; then (B) forming a photosensitive material layer 35 over the second compound semiconductor layer 22; and thereafter (C) exposing the photosensitive material layer 35 to light from the concave mirror section side through the stacked structure 20, to obtain a treatment mask layer including the photosensitive material layer 35, and then processing the second compound semiconductor layer 22 by use of the treatment mask layer.