Abstract: Resonant-cavity infrared photodetector (RCID) devices that include a thin absorber layer contained entirely within the resonant cavity. In some embodiments, the absorber region is a single type-II InAs—GaSb interface situated between an n-type region comprising an AlSb/InAs n-type superlattice and a p-type AlSb/GaSb region. In other embodiments, the absorber region comprises one or more quantum wells formed on an upper surface of the n-type region. In other embodiments, the absorber region comprises a “W”-structured quantum well situated between two barrier layers, the “W”-structured quantum well comprising a hole quantum well sandwiched between two electron quantum wells. In other embodiments, an RCID in accordance with the present invention includes a thin absorber region and an nBn or pBp active core within a resonant cavity.

Abstract: Resonant-cavity infrared photodetector (RCID) devices that include a thin absorber layer contained entirely within the resonant cavity. In some embodiments, the absorber is a single type-II InAs-GaSb interface situated between an AlSb/InAs superlattice n-type region and a p-type AlSb/GaSb region. In other embodiments, the absorber region comprises quantum wells formed on an upper surface of the n-type region. In other embodiments, the absorber region comprises a “W”-structured quantum well situated between two barrier layers, the “W”-structured quantum well comprising a hole quantum well sandwiched between two electron quantum wells. In other embodiments, the RCID includes a thin absorber region and an nBn or pBp active core within a resonant cavity. In some embodiments, the RCID is configured to absorb incident light propagating in the direction of the epitaxial growth of the RCID structure, while in other embodiments, it absorbs light propagating in the epitaxial plane of the structure.

Abstract: 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.

Abstract: A DFB laser having a reduced fill factor and reduced loss. A plurality of spaced-apart contact openings are etched into a dielectric layer situated on top of a laser ridge having a DFB grating layer so that electrical contact between the metal top contact layer and the DFB gratings is made only in the etched openings, since all other areas of the top surface of the DFB-grated laser ridge are insulated from the metal contact layer by the dielectric. The size and shape of contact openings and their spacing are configured so that the ratio of the total area of the openings to the total area of the laser ridge provides a fill factor of less than 100%.

Abstract: 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.

Abstract: Resonant-cavity infrared photodetector (RCID) devices that include a thin absorber layer contained entirely within the resonant cavity. In some embodiments, the absorber region is a single type-II InAs—GaSb interface situated between an n-type region comprising an AlSb/InAs n-type superlattice and a p-type AlSb/GaSb region. In other embodiments, the absorber region comprises one or more quantum wells formed on an upper surface of the n-type region. In other embodiments, the absorber region comprises a “W”-structured quantum well situated between two barrier layers, the “W”-structured quantum well comprising a hole quantum well sandwiched between two electron quantum wells. In other embodiments, an RCID in accordance with the present invention includes a thin absorber region and an nBn or pBp active core within a resonant cavity.

Abstract: An ultra-broadband photonic integrated circuit platform that combines at least two types of waveguides that each transmit in different, but overlapping, spectral bands on a single chip. By combining the multiple waveguides, the bandwidth of the platform can be extended beyond the bandwidth of either waveguide alone. In an exemplary embodiment, an ultra-broadband photonic integrated circuit includes a nitride-on-insulator (NOI) waveguide configured to transmit optical beams in a first spectral band and a silicon-on-nitride-on-insulator (SONOI) waveguide configured to transmit optical beams in a second band, where the same material serves as the core material in the NOI waveguide and as the cladding material in the SONOI waveguide. In some embodiments, light-emitting devices are bonded to an upper surface of the waveguides. In some embodiments, the circuit includes beam-combining elements so that a single beam combining all of the input wavelengths is output from the circuit.

Abstract: A DFB laser having a reduced fill factor and reduced loss. A plurality of spaced-apart contact openings are etched into a dielectric layer situated on top of a laser ridge having a DFB grating layer so that electrical contact between the metal top contact layer and the DFB gratings is made only in the etched openings, since all other areas of the top surface of the DFB-grated laser ridge are insulated from the metal contact layer by the dielectric. The size and shape of contact openings and their spacing are configured so that the ratio of the total area of the openings to the total area of the laser ridge provides a fill factor of less than 100%.

Abstract: An ultra-broadband photonic integrated circuit platform that combines at least two types of waveguides that each transmit in different, but overlapping, spectral bands on a single chip. By combining the multiple waveguides, the bandwidth of the platform can be extended beyond the bandwidth of either waveguide alone. In an exemplary embodiment, an ultra-broadband photonic integrated circuit includes a nitride-on-insulator (NOI) waveguide configured to transmit optical beams in a first spectral band and a silicon-on-nitride-on-insulator (SONOI) waveguide configured to transmit optical beams in a second band, where the same material serves as the core material in the NOI waveguide and as the cladding material in the SONOI waveguide. In some embodiments, light-emitting devices are bonded to an upper surface of the waveguides. In some embodiments, the circuit includes beam-combining elements so that a single beam combining all of the input wavelengths is output from the circuit.

Abstract: A computationally efficient method for building a superlattice structure that improves an optoelectronic device performance characteristic that depends on fundamental superlattice material properties such as absorption coefficient ?(?), radiative efficiency Rsp and/or electron density n.

Abstract: A multijunction (MJ) solar cell grown on an InP substrate using materials that are lattice-matched to InP. In an exemplary three-junction embodiment, the top cell is formed from In1-xAlxAs1-ySby (with x and y adjusted so as to achieve lattice-matching with InP, hereafter referred to as InAlAsSb), the middle cell from In1-a-bGaaAlbAs (with a and b adjusted so as to achieve lattice-matching with InP, hereafter referred to as InGaAlAs), and the bottom cell also from InGaAlAs, but with a much lower Al composition, which in some embodiments can be zero so that the material is InGaAs. Tunnel junctions (TJs) connect the junctions and allow photo-generated current to flow. In an exemplary embodiment, an InAlAsSb TJ connects the first and second junctions, while an InGaAlAs TJ connects the second and third junctions.

Abstract: Methods for improving the performance of type-II and type-I ICLs, particularly in the mid-IR wavelength range, are provided. The electron injector of a type-II or a type-I ICL can be heavily n-doped to increase the ratio of electrons to holes in the active quantum wells, thereby increasing the probability of radiative recombination in the active quantum wells and reducing the threshold current density Jth needed to achieve lasing. For both type-II and type-I ICLs, the doping should have a sheet density in the low-1012 range. In either the type-II or the type-I case, in some embodiments, heavy doping can be concentrated in the middle quantum wells of the electron injector, while in other embodiments, doping with silicon can be shifted towards the active quantum wells.

Abstract: Methods for improving the performance of type-II and type-I ICLs, particularly in the mid-IR wavelength range, are provided. The electron injector of a type-II or a type-I ICL can be heavily n-doped to increase the ratio of electrons to holes in the active quantum wells, thereby increasing the probability of radiative recombination in the active quantum wells and reducing the threshold current density Jth needed to achieve lasing. For both type-II and type-I ICLs, the doping should have a sheet density in the low-1012 range. In either the type-II or the type-I case, in some embodiments, heavy doping can be concentrated in the middle quantum wells of the electron injector, while in other embodiments, doping with silicon can be shifted towards the active quantum wells.

Abstract: A laser apparatus configured for epitaxial-side-down mounting on a heat sink. The laser apparatus includes a semiconductor laser structure and at least one post on a substrate where the laser structure and post are separated from each other by a channel. The laser structure and the posts optionally are coated with a heat-spreading material layer and are configured so that the maximum height of the posts is about the same as the maximum height of the laser structure. When the laser apparatus is mounted to a heat sink in an epi-down configuration using solder applied to the top of the laser structure and the at least one post, the channels between the at least one post and the laser structure provide a relief flow path for the solder and ensure that the laser structure does not come directly into contact with the solder.

Abstract: Methods for improving the performance of type-II and type-I ICLs, particularly in the mid-IR wavelength range, are provided. The electron injector of a type-II or a type-I ICL can be heavily n-doped to increase the ratio of electrons to holes in the active quantum wells, thereby increasing the probability of radiative recombination in the active quantum wells and reducing the threshold current density Jth needed to achieve lasing. For both type-II and type-I ICLs, the doping should have a sheet density in the low-1012 range. In either the type-II or the type-I case, in some embodiments, heavy doping can be concentrated in the middle quantum wells of the electron injector, while in other embodiments, doping with silicon can be shifted towards the active quantum wells.

Abstract: A laser apparatus configured for epitaxial-side-down mounting on a heat sink. The laser apparatus includes a semiconductor laser structure and at least one post on a substrate where the laser structure and post are separated from each other by a channel. The laser structure and the posts optionally are coated with a heat-spreading material layer and are configured so that the maximum height of the posts is about the same as the maximum height of the laser structure. When the laser apparatus is mounted to a heat sink in an epi-down configuration using solder applied to the top of the laser structure and the at least one post, the channels between the at least one post and the laser structure provide a relief flow path for the solder and ensure that the laser structure does not come directly into contact with the solder.

Abstract: An interband cascade gain medium is provided. The gain medium can include at least one thick separate confinement layer comprising Ga(InAlAs)Sb between the active gain region and the cladding and can further include an electron injector region having a reduced thickness, a hole injector region comprising two hole quantum wells having a total thickness greater than about 100 ?, an active gain quantum well region separated from the adjacent hole injector region by an electron barrier having a thickness sufficient to lower a square of a wavefunction overlap between a zone-center active electron quantum well and injector hole states, and a thick AlSb barrier separating the electron and hole injectors of at least one stage of the active region.

Abstract: A multijunction (MJ) solar cell grown on an InP substrate using materials that are lattice-matched to InP. In an exemplary three-junction embodiment, the top cell is formed from In1-xAlxAs1-ySby (with x and y adjusted so as to achieve lattice-matching with InP, hereafter referred to as InAlAsSb), the middle cell from In1-a-bGaaAlbAs (with a and b adjusted so as to achieve lattice-matching with InP, hereafter referred to as InGaAlAs), and the bottom cell also from InGaAlAs, but with a much lower Al composition, which in some embodiments can be zero so that the material is InGaAs. Tunnel junctions (TJs) connect the junctions and allow photo-generated current to flow. In an exemplary embodiment, an InAlAsSb TJ connects the first and second junctions, while an InGaAlAs TJ connects the second and third junctions.

Abstract: A gain medium and an interband cascade laser, having the gain medium are presented. The gain medium can have one or both of the following features: (1) the thicknesses of the one or more hole quantum wells in the hole injector region are reduced commensurate with the thickness of the active hole quantum well in the active quantum well region, so as to place the valence band maximum in the hole injector region at least about 100 meV lower than the valence band maximum in the active hole quantum well; and (2) the thickness of the last well of the electron injector region is between 85 and 110% of the thickness of the first active electron quantum well in the active gain region of the next stage of the medium. A laser incorporating a gain medium in accordance with the present invention can emit in the mid-IR range from about 2.5 to 8 ?m at high temperatures with room-temperature continuous wave operation to wavelengths of at least 4.

Abstract: A gain medium and an interband cascade laser, having the gain medium are presented. The gain medium can have one or both of the following features: (1) the thicknesses of the one or more hole quantum wells in the hole injector region are reduced commensurate with the thickness of the active hole quantum well in the active quantum well region, so as to place the valence band maximum in the hole injector region at least about 100 meV lower than the valence band maximum in the active hole quantum well; and (2) the thickness of the last well of the electron injector region is between 85 and 110% of the thickness of the first active electron quantum well in the active gain region of the next stage of the medium. A laser incorporating a gain medium in accordance with the present invention can emit in the mid-IR range from about 2.5 to 8 ?m at high temperatures with room-temperature continuous wave operation to wavelengths of at least 4.