A vertical-cavity surface-emitting laser (VCSEL) has at least a substrate, electrical contacts, a first mirror region, a second mirror region and an active region between the mirror regions; where the mirror regions comprise distributed Bragg reflectors formed of a plurality of layers; laser emission is from at least one gallium arsenide antimonide nanostructure in the active region; and each said nanostructure contains more antimony atoms than arsenic atoms.

A semiconductor laser includes an active layer which is provided between the p-type semiconductor region and the n-type semiconductor region and has a type II quantum well structure. The type II quantum well structure includes a well layer made of a III-V compound semiconductor and a plurality of barrier layers. The well layer includes a first region and a second region, the first region having a low potential for electrons in the well layer and a high potential for holes in the well layer, the second region having a high potential for electrons in the well layer and a low potential for holes in the well layer. The first region and the second region of the well layer are arranged in a direction from one of the barrier layers to another of the barrier layers.

Disclosed is an electrically pumped vertical cavity laser structure operating in the mid-infrared region, which has demonstrated room-temperature continuous wave operation. This structure uses an interband cascade gain region, two distributed mirrors, and a low-loss refractive index waveguide. A preferred embodiment includes at least one wafer bonded GaAs-based mirror.

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.

A semiconductor crystal substrate includes: a crystal substrate whose principal surface is inclined relative to a (001) plane; and a superlattice structure layer including a first superlattice formation layer and a second superlattice formation layer, wherein the first superlattice formation layer is formed of Ga.sub.1-x1In.sub.x1As.sub.y1Sb.sub.1-y1 (0x10.1, 0y10.1), and a value of a standard deviation to a mean value of atomic step widths in an inclination direction is equal to or greater than 0 and equal to or smaller than 0.20, and the second superlattice formation layer is formed of Ga.sub.1-x2In.sub.x2As.sub.y2Sb.sub.1-y2 (0.9x21, 0.9y21), and a value of a standard deviation to a mean value of atomic step widths in an inclination direction is equal to or greater than 0 and equal to or smaller than 0.40.

A laser radar device includes a transmitter, a receiver, and an optical coupler. The optical coupler includes an incident surface, an emergent surface, and a reflective surface. At least one convergent lens is positioned at the incident surface. The convergent lens is aligned with the transmitter and the receiver. At least one collimating lens is positioned at the emergent surface. The at least one collimating lens corresponds to the at least one convergent lens. An angle between the reflective surface and the incident surface is equal to an angle between the reflective surface and the emergent surface.

The invention relates to an optoelectronic component (1) that is insensitive to dislocations, comprising:

a semiconductor heterostructure (2) able to emit laser radiation, said semiconductor heterostructure being formed from first semiconductors comprising a cascade of gain-providing active regions (21) in which the inter-band radiative transition is of type II, and

a carrier structure (30) comprising a non-native substrate (3) different from the first semiconductors, said semiconductor heterostructure (2) being formed by epitaxial growth on the carrier structure (30),

wherein the active regions have a dislocation density higher than 10.sup.7 .cm.sup.?2.

A nitride semiconductor device includes a GaN substrate in which an angle between a principal surface and an m-plane of GaN is 5 or more and +5 or less, a first intermediate layer disposed on the principal surface of the substrate and made of Al.sub.zGa.sub.(1z)N, 0z1, and a second intermediate layer disposed on a principal surface of the first intermediate layer, having an Al content different from that of the first intermediate layer, and made of Al.sub.x1In.sub.y1Ga.sub.(1x1y1)N, 0x11, 0y11. A quantum cascade laser includes the nitride semiconductor device.

Novel ICL layering designs, ridge waveguide architectures, and processing protocols that will significantly lower the optical losses and improve the power conversion efficiencies of interband cascade lasers designed for both DFB single-mode and high-power applications. The semiconductor top cladding and metal contact layers are eliminated or significantly reduced. By instead using a dielectric or air top clad, or dielectric or air layers to supplement a thin top clad, in conjunction with lateral current injection and weak index-guiding, the present invention will substantially reduce the internal loss of such ICLs, resulting in lower lasing threshold, higher efficiency, and higher maximum power.

A vertical-cavity surface-emitting laser (VCSEL) has at least a substrate, electrical contacts, a first mirror region, a second mirror region and an active region between the mirror regions; where the mirror regions comprise distributed Bragg reflectors formed of a plurality of layers; laser emission is from at least one gallium arsenide antimonide nanostructure in the active region; and each said nanostructure contains more antimony atoms than arsenic atoms.