Abstract: A quantum well infrared photodetector (QWIP) and method of making is disclosed. The QWIP includes a plurality of epi-layers formed into multiple periods of quantum wells, each of the quantum wells being separated by a barrier, the quantum wells and barriers being formed of II-VI semiconductor materials. A multiple wavelength QWIP is also disclosed and includes a plurality of QWIPs stacked onto a single epitaxial structure, in which the different QWIPs are designed to respond at different wavelengths. A dual wavelength QWIP is also disclosed and includes two QWIPs stacked onto a single epitaxial structure, in which one QWIP is designed to respond at 10 ?m and the other at 3-5 ?m wavelengths.

Abstract: A high power quantum cascade superluminescent emitter employs low reflectivity facets including a tilted cleaved facet, a rounded shaped wet-etched sloped facet and a loop facet in either a linear or spiral configuration to increase ASE.

Abstract: A quantum cascade laser and method of making are disclosed. The quantum cascade laser includes a plurality stages configured in a cascade structure, each stage having a quantum well emission layer and an injection layer, each stage having an upper laser level and a lower laser level. A scattering barrier is located in the quantum well emission layer, the scattering barrier being positioned such that interface roughness (IFR) scattering at the lower laser level is greater than IFR scattering at the upper laser level. The scattering barrier may be located to maximize IFR scattering for the lower laser level and/or minimize IFR scattering for the upper laser level.

Abstract: Single-mode quantum cascade lasers having shaped cavities of various geometries are provided. The shaped cavities function as monolithic coupled resonators, and permit single-mode operation of the lasers. A folded or hairpin-shaped cavity could be provided, having a plurality of straight segments interconnected with a curved segment. Additionally, a shaped cavity could be provided having a single straight segment interconnected at one end to a curved segment. The curved segment could also be tapered in shape, such that the width of the curved segment decreases toward one end of the curved segment. A laser which includes a shaped cavity having two interconnected, folded shaped cavities is also provided.

Abstract: A quantum well infrared photodetector (QWIP) and method of making is disclosed. The QWIP includes a plurality of epi-layers formed into multiple periods of quantum wells, each of the quantum wells being separated by a barrier, the quantum wells and barriers being formed of II-VI semiconductor materials. A multiple wavelength QWIP is also disclosed and includes a plurality of QWIPs stacked onto a single epitaxial structure, in which the different QWIPs are designed to respond at different wavelengths. A dual wavelength QWIP is also disclosed and includes two QWIPs stacked onto a single epitaxial structure, in which one QWIP is designed to respond at 10 ?m and the other at 3-5 ?m wavelengths.

Abstract: The present invention relates to a rotationally asymmetric chaotic optical multi-pass cavity useful in optical gas sensing spectroscopy, optical delay lines, and laser amplification systems, for example. The cavity may include a single closed mirror having a light reflective surface that is deformed in two orthogonal directions and more particularly, but not exclusively, in the shape of a quadrupole in both horizontal and vertical planes. The cavity includes a light entry port and a light exit port which may be the same or separate ports, as well as a gas inlet and a gas outlet. The optical path length, the beam divergence rate, and the spot pattern are controlled by selecting the cavity deformation coefficients and the input beam direction to achieve the desired beam path and beam quality.

Abstract: Single-mode quantum cascade lasers having shaped cavities of various geometries are provided. The shaped cavities function as monolithic coupled resonators, and permit single-mode operation of the lasers. A folded or hairpin-shaped cavity could be provided, having a plurality of straight segments interconnected with a curved segment. Additionally, a shaped cavity could be provided having a single straight segment interconnected at one end to a curved segment. The curved segment could also be tapered in shape, such that the width of the curved segment decreases toward one end of the curved segment. A laser which includes a shaped cavity having two interconnected, folded shaped cavities is also provided.

Abstract: The present invention relates to a rotationally asymmetric chaotic optical multi-pass cavity useful in optical gas sensing spectroscopy, optical delay lines, and laser amplification systems, for example. The cavity may include a single closed mirror having a light reflective surface that is deformed in two orthogonal directions and more particularly, but not exclusively, in the shape of a quadrupole in both horizontal and vertical planes. The cavity includes a light entry port and a light exit port which may be the same or separate ports, as well as a gas inlet and a gas outlet. The optical path length, the beam divergence rate, and the spot pattern are controlled by selecting the cavity deformation coefficients and the input beam direction to achieve the desired beam path and beam quality.

Abstract: A broadband CLE capable of operation simultaneously at multiple wavelengths comprises: a core region including a multiplicity or cascade of stages, each stage including a radiative transition region. A first group of stages emits radiation at a first wavelength and at a first aggregate intensity per group, and a second group of stages emits radiation at a second wavelength and at a second aggregate intensity per group lower than the first intensity. The invention is characterized in that the second group has more stages than said first group, and the per-stage intensity of the first group is greater than that of the second group. This design reduces the difference between said first and second aggregate intensities. In one embodiment, groups that are located at or near to the ends of the cascade have more stages than groups that are centrally located within the cascade regardless of their wavelength.

Abstract: An optical device comprises a cavity resonator and an intracavity ridge waveguide. The ridge waveguide includes a monolithically integrated intersubband core region and a nonlinear mixing region (NMR). In response to external pumping energy the core region generates laser light at a first frequency and in a first transverse mode. In response to the laser light the NMR generates parametric light at a second frequency and in a second transverse mode. For phase matching the effective-refractive-index-versus-ridge-width characteristics of the modes of the laser and the parametric light intersect one another at a phase matching width and so that, at greater widths, the effective refractive index of the mode of the higher frequency light is less than that of the lower frequency light. For true phase matching the width of the ridge is made to be essentially equal to the phase matching width.

Abstract: An optoelectronic transducer comprises a unipolar, intraband active region and a micro-cavity resonator. The resonator includes a 2D array of essentially equally spaced regions that exhibits resonant modes. Each of the spaced regions has a depth that extends through the active region and has an average refractive index that is different from that of the active region. The refractive index contrast, the spacing of the spaced regions, and the dimensions of the spaced regions are mutually adapted so that the array acts as a micro-cavity resonator and so that at least one frequency of the resonant modes of the array falls within the spectrum of an optoelectronic parameter of the active region (i.e., the gain spectrum where the transducer is a laser; the absorption spectrum where the transducer is a photodetector). In a first embodiment, the transducer is an ISB laser, whereas in a second embodiment it is a unipolar, intraband photodetector.

Abstract: In a mesa geometry semiconductor laser, a patterned dielectric coating used to define the stripe geometry contact on the top the mesa and to provide significant waveguiding comprises a chalcogenide glass. Applications to intersubband (e.g., quantum cascade) lasers are specifically described.

Abstract: A mounting technology that increases the cw operating temperature of intersubband lasers, without increasing the risk of hot spots near the facets and short circuits near the perimeter of the laser chip, is described.