Disclosed is an optically pumped vertical cavity laser structure operating in the mid-infrared region, which has demonstrated room-temperature continuous wave operation. This structure uses a periodic gain active region with type I quantum wells comprised of InGaAsSb, and barrier/cladding regions which provide strong hole confinement and substantial pump absorption. A preferred embodiment includes at least one wafer bonded GaAs-based mirror. Several preferred embodiments also include means for wavelength tuning of mid-IR VCLs as disclosed, including a MEMS-tuning element. This document also includes systems for optical spectroscopy using the VCL as disclosed, including systems for detection concentrations of industrial and environmentally important gases.

Tunable VCSELs (TVCSELs) employing expanded material systems with expanded mechanical/optical design space for semiconductor DBR mirrors on GaAs substrates. One is the InGaAs/AlGaAsP material system. It adds indium In to decrease InGaAs H-layer bandgap for higher refractive index and higher DBR layer refractive index contrast. Adding phosphorus P gives independent control of bandgap and strain of AlGaAsP low refractive index L-layers. The tensile strain of AlGaAsP L-layer compensates compressive strain of InGaAs H-layer and lowers the cumulative strain of the multilayer DBR structure. Another option is the InGaAsN(Sb)/AlGaAsP material system, where both types of layers can be lattice matched to GaAs. It uses indium In and nitrogen N, and possibly antimony Sb, to get independent control of strain and bandgap, and thus refractive index, of dilute nitride InGaAsN(Sb) H-layers, with lower bandgap and higher refractive index than starting GaAs. Using expanded material system enables reliable DBR mirrors with higher reflectivity and spectral bandwidth and tunable VCSELs with wider tuning range.

A light source package structure is provided. The light source package structure includes a substrate, an upper electrode layer, a surrounding wall, a light emitting unit, an adhesive, and a light permeable element. The surrounding wall is annular with step structure and includes an upper tread surface arranged away from the substrate, an upper riser surface connected to an inner edge of the upper tread surface, a lower tread surface disposed at an inner side of the upper riser surface, an accommodating groove disposed between the lower tread surface and the upper riser surface, and a lower riser surface connected to an inner edge of the lower tread surface and arranged away from the upper tread surface. The lower riser surface and the first surface jointly define a receiving space.

Quantum well designs for tunable VCSELs are disclosed that are tolerant of the wavelength shift. Specifically, the active region has even number of substantially uniformly spaced (¼ of the center wavelength in the semiconducting material) quantum wells.

A tunable laser assembly housed in a single enclosure and a method of control is described that provides high-speed monitoring and control of the spectral properties of widely tunable lasers, such as MEMS-tunable VCSELs, with an optical configuration that does not introduce perturbations into the swept-source laser output spectrum that would cause artifacts in imaging applications such as optical coherence tomography (OCT).

A surface-emitting laser includes an output unit. The output unit has an oblong-shaped VCSEL (vertical-cavity surface-emitting laser) structure. The output unit operates in an oscillation state in which a current that is larger than the oscillation threshold value is injected. The output unit receives a coherent seed light via a coupling surface at one end of the VCSEL structure in the longitudinal direction thereof. The seed light thus received propagates as a slow light through the VCSEL structure in the longitudinal direction thereof while being reflected multiple times in the vertical direction within the VCSEL structure. An output light is extracted from the upper surface of the VCSEL structure.

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 tunable laser assembly housed in a single enclosure and a method of control is described wherein the tunable laser, pump and semiconductor optical amplifier do not share a common optical axis but are all aligned to optical waveguides on an intervening planar lightwave circuit (PLC). Wavelength monitoring circuitry is included on the PLC to enable monitoring and control of the tunable laser center wavelength and optical bandwidth. The design of the PLC does not introduce perturbations into the swept-source laser output spectrum that would cause artifacts in imaging applications such as optical coherence tomography (OCT).

A tunable laser assembly housed in a single enclosure and a method of control is described wherein the tunable laser, pump and semiconductor optical amplifier do not share a common optical axis but are all aligned to optical waveguides on an intervening planar lightwave circuit (PLC). Wavelength monitoring circuitry is included on the PLC to enable monitoring and control of the tunable laser center wavelength and optical bandwidth. The design of the PLC does not introduce perturbations into the swept-source laser output spectrum that would cause artifacts in imaging applications such as optical coherence tomography (OCT).

A vertical cavity surface emitter device (e.g., VCSEL or RC-LED) containing a buried index-guiding current confinement aperture layer which is grown, and lithographically processed to define position, shape and dimension of an inner aperture. In a regrowth process, the aperture is filled with a single crystalline material from the third contact layer. The aperture provides for both current and optical confinement, while allowing for higher optical power output and improved thermal conductivity.