A semiconductor laser diode is disclosed. In an embodiment a semiconductor laser diode includes a first resonator and a second resonator, the first and second resonators having parallel resonator directions along a longitudinal direction and being monolithically integrated into the semiconductor laser diode, wherein the first resonator includes at least a part of a semiconductor layer sequence having an active layer and an active region configured to be electrically pumped to generate a first light, wherein the longitudinal direction is parallel to a main extension plane of the active layer, and wherein the second resonator has an active region with a laser-active material configured to be optically pumped by at least a part of the first light to produce a second light which is partially emitted outwards from the second resonator.

An active layer of a quantum cascade laser includes an active layer includes a plurality of emission regions and a plurality of injection regions. Each emission region includes an injection barrier layer, and an light-emitting quantum well layer that has at least two well layers, and that emits infrared light by undergoing an intersubband transition. Each injection region includes an extraction barrier layer, and a relaxation quantum well layer that creates an energy level for relaxing the energy of carriers from the each emission region. One of adjacent two well layers in the light-emitting quantum well layer of the each emission region on the side of the extraction barrier layer is deeper than a second well layer on the side of the injection barrier layer. The each emission region and the injection region are alternately stacked.

Structures described herein may include mechanically bonded interlayers for formation between a first Group III-V semiconductor layer and a second semiconductor layer. The mechanically bonded interlayers provide reduced lattice strain by strain balancing between the Group III-V semiconductor layer and the second semiconductor layer, which may be silicon.

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 optical device includes a substrate of a first conductivity type; an optical confinement layer of the first conductivity type, which is arranged above the substrate of the first conductivity type; a multi quantum well layer, which is arranged above the optical confinement layer of the first conductivity type, and comprises a plurality of well layers and a plurality of barrier layers; an optical confinement layer of a second conductivity type, which is arranged on the multi quantum well layer; and a PL stabilization layer, which is arranged between the substrate of the first conductivity type and the multi quantum well layer. The PL stabilization layer having a thickness that is half a thickness of the multi quantum well layer or more, and having a composition wavelength that is shorter than a composition wavelength of the plurality of well layers of the multi quantum well layer.

A semiconductor component for emitting light includes a main body that comprises at least one mesa body. The mesa body has an emission region for emitting the light. The emission region is assigned a first mirror portion, a second mirror portion, and an active portion arranged between the two mirror portions and serving to produce the light. The semiconductor component further includes electrical contacts for feeding electrical energy into the active portion, with at least one stress element that is attached to a surface of the main body. The stress element is configured to generate in the main body a material stress which has an effect on one or more polarization properties of the emitted light.

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 optical device (40, 50, 60) comprises a first region 42 comprising an active region configured such that electrons and holes recombine in the active region to produce photons when a voltage is applied to the device. The device comprises at least one second region (43, 44, 53, 54, 62, 63) comprising a quantum well structure which is configured to trap electrons only, to trap holes only, or to trap different amounts of electrons and holes. The second region is arranged at a distance from the first region which is sufficiently close to the first region such that a charge imbalance develops in the first region when a voltage is applied to the device, thereby to reduce Auger recombination in the first region.

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 gallium- and nitrogen-containing laser device including an etched facet with surface treatment to improve an optical beam is disclosed.