A Vertical Cavity Surface Emitting Laser (VCSEL) includes a layer stack of semiconductor layers having a first layer sub-stack forming a mesa, and a second layer sub-stack adjacent to the mesa in a stacking direction. Layers of the second layer sub-stack extend beyond layers of the first sub-stack in a direction perpendicular to the stacking direction. The semiconductor layers of the layer stack form an optical resonator having a first mirror, a second mirror, an active region between the first and second mirrors for laser light generation, and an oxide aperture layer forming a current aperture. The oxide aperture layer is made from Al.sub.1-xGa.sub.xAs with 0≤x≤0.05. The oxide aperture layer is a last layer of the mesa and immediately adjacent to a first layer of the second layer sub-stack. A first layer of the second layer sub-stack is a contact layer.

Building blocks are provided for on-chip chemical sensors and other highly-compact photonic integrated circuits combining interband or quantum cascade lasers and detectors with passive waveguides and other components integrated on a III-V or silicon. A MWIR or LWIR laser source is evanescently coupled into a passive extended or resonant-cavity waveguide that provides evanescent coupling to a sample gas (or liquid) for spectroscopic chemical sensing. In the case of an ICL, the uppermost layer of this passive waveguide has a relatively high index of refraction that enables it to form the core of the waveguide, while the ambient air, consisting of the sample gas, functions as the top cladding layer. A fraction of the propagating light beam is absorbed by the sample gas if it contains a chemical species having a fingerprint absorption feature within the spectral linewidth of the laser emission.

The invention relates to a semiconductor laser comprising a layer structure comprising an active zone, wherein the active zone is configured to generate an electromagnetic radiation, wherein the layer structure comprises a sequence of layers, wherein two opposite end faces are provided in a Z-direction, wherein at least one end face is configured to at least partly couple out the electromagnetic radiation, and wherein the second end face is configured to at least partly reflect the electromagnetic radiation, wherein guide means are provided for forming an optical mode in a mode space between the end faces, wherein means are provided which hinder a formation of an optical mode outside the mode space, in particular modes comprising a propagation direction which do not extend perpendicularly to the end faces.

A laser diode includes a substrate, an epitaxial structure, an electrode contacting layer and an optical cladding layer. The epitaxial structure is disposed on the substrate, and is formed with a ridge structure opposite to the substrate. The electrode contacting layer is disposed on a top surface of the ridge structure. The optical cladding layer has a refractive index smaller than that of the electrode contacting layer The optical cladding layer includes a first cladding portion which covers side walls of the ridge structure, and a second cladding portion which is disposed on a portion of the top surface of the ridge structure. A method for manufacturing the abovementioned laser diode is also disclosed.

Ohmic contacts, including materials and processes for forming n-type ohmic contacts on n-type semiconductor substrates at low temperatures, are disclosed. Materials include reactant layers, n-type dopant layers, capping layers, and in some instances, adhesion layers. The capping layers can include metal layers and diffusion barrier layers. Ohmic contacts can be formed on n-type semiconductor substrates at temperatures between 150 and 250° C., and can resist degradation during operation.

A power over fiber system includes a power sourcing equipment, a powered device, an optical fiber cable, a measurer and a control device. The power sourcing equipment includes a semiconductor laser that oscillates with electric power, thereby outputting feed light. The powered device includes a photoelectric conversion element that converts the feed light into electric power. The optical fiber cable transmits the feed light from the power sourcing equipment to the powered device. The measurer measures a distance from the power sourcing equipment to the powered device. The control device controls the power sourcing equipment to output the feed light by changing a laser wavelength thereof for the distance from the power sourcing equipment to the powered device measured by the measurer.

A manufacturing method of a nitride-based semiconductor light-emitting element includes: forming an n-type nitride-based semiconductor layer; forming, on the n-type nitride-based semiconductor layer, a light emission layer including a nitride-based semiconductor; forming, on the light emission layer in an atmosphere containing a hydrogen gas, a p-type nitride-based semiconductor layer while doping the p-type nitride-based semiconductor layer with a p-type dopant at a concentration of at least 2.0×10.sup.18 atom/cm.sup.3; and annealing the p-type nitride-based semiconductor layer at a temperature of at least 800 degrees Celsius in an atmosphere not containing hydrogen. In this manufacturing method, a hydrogen concentration of the p-type nitride-based semiconductor layer after the annealing is at most 5.0×10.sup.18 atom/cm.sup.3 and at most 5% of the concentration of the p-type dopant, and a hydrogen concentration of the light emission layer is at most 2.0×10.sup.17 atom/cm.sup.3.

In an example, the present invention provides a gallium and nitrogen containing structure. The structure has a plurality of gallium and nitrogen containing semiconductor substrates, each of the gallium and nitrogen containing semiconductor substrates having one or more epitaxially grown layers. The structure has a first handle substrate coupled to each of the substrates. The orientation of a reference crystal direction for each of the substrates are parallel to within 10 degrees or less. The structure has a first bonding medium provided between the first handle substrate and each of the substrates.

A laser element comprises a substrate; and an n-type semiconductor layer, a light emitting layer, a p-type semiconductor layer, and an electrode layer successively laminated on one principal surface of the substrate, wherein the p-type semiconductor layer includes a ridge raised in a stripe shape, the ridge including a contact layer formed in a layer including a principal surface on a side opposite to the substrate, a stepped portion defined by recessing the contact layer is formed in at least part of a boundary between a lateral surface among surfaces defining outer edges of the ridge, the lateral surface extending along a lengthwise direction of the ridge, and the principal surface of the ridge, and the electrode layer covers the principal surface of the ridge and the stepped portion.

A surface emitting laser includes a substrate, a mesa of semiconductor layers including a lower reflector layer, an active layer, an upper reflector layer, and an upper contact layer that are successively laminated on the substrate, and an electrode provided on the upper contact layer. The upper contact layer includes GaAs. The electrode includes an alloy layer including Pt, in contact with the upper contact layer.