Abstract: Semiconductor structures and laser devices including the semiconductor structures are provided. The semiconductor structures have a quantum cascade laser (QCL) structure including an electron injector, an active region, and an electron extractor. The active region of the semiconductor structures includes a configuration of quantum wells and barriers that virtually suppresses electron leakage, thereby providing laser devices including such structures with superior electro-optical characteristics.

Abstract: An intersubband quantum cascade laser structure includes multiple coupled laser stages, wherein each stage has a multilayer structure including an electron injector, an active region with at least one quantum well, and an electron reflector. Electrons injected from the injector into the active region at a high energy level relax to a lower energy level with the emission of a photon at, for example, mid-infrared wavelengths. The reflector reflects electrons at the higher energy level at which they were injected and transmits electrons from the lower energy level after emission of a photon. Multiple layers of semiconductor are formed on each side of the multistage structure to provide conduction across the device and to provide optical confinement of the photons emitted.

Abstract: A semiconductor laser and light emitting device is defined. The device comprises an electron injector and an active region adjacent to the electron injector. The active region includes at least one deep quantum well with barrier layers adjacent to either side of the quantum well or wells such that electrons injected from the electron injector into a high energy level of the quantum well relax to a lower energy level with the emission of a photon and are transmitted out to a region beyond the last barrier layer of the active region. The electron injector includes quantum well layers. The bottom of each deep quantum well or wells in the active region is lower in energy than the bottoms of the quantum well layers in the electron injector. The device may further comprise at least two stages wherein each stage contains an electron injector and an active region.

Abstract: An intersubband quantum cascade laser structure includes multiple coupled laser stages, wherein each stage has a multilayer structure including an electron injector, an active region with at least one quantum well, and an electron reflector. Electrons injected from the injector into the active region at a high energy level relax to a lower energy level with the emission of a photon at, for example, mid-infrared wavelengths. The reflector reflects electrons at the higher energy level at which they were injected and transmits electrons from the lower energy level after emission of a photon. Multiple layers of semiconductor are formed on each side of the multistage structure to provide conduction across the device and to provide optical confinement of the photons emitted.

Abstract: A semiconductor laser is formed on a semiconductor substrate with an array of laterally spaced laser device elements each including a second order distributed feedback grating bounded by distributed Bragg reflector gratings. The device elements in which the distributed feedback grating and the distributed Bragg reflector gratings are formed have a lower effective index than the index of the interelement regions and are spaced so as to form an antiguided array.

Abstract: The present invention provides semiconductor lasers having an Active-Photonic-Crystal (APC) structure that allows scaling of the coherent power by using a waveguide having a periodic structure that selects operation in a single spatial mode from large-aperture devices. The lasers include an active medium that includes an array of quantum box ministacks, each ministack containing 2 to 5 vertically stacked, coupled quantum boxes.

Abstract: An intersubband quantum cascade laser structure includes multiple coupled laser stages, wherein each stage has a multilayer structure including an electron injector, an active region with at least one quantum well, and an electron reflector. Electrons injected from the injector into the active region at a high energy level relax to a lower energy level with the emission of a photon at, for example, mid-infrared wavelengths. The reflector reflects electrons at the higher energy level at which they were injected and transmits electrons from the lower energy level after emission of a photon. Multiple layers of semiconductor are formed on each side of the multistage structure to provide conduction across the device and to provide optical confinement of the photons emitted.

Abstract: The present invention provides semiconductor lasers having an Active-Photonic-Crystal (APC) structure that allows scaling of the coherent power by using a waveguide having a periodic structure that selects operation in a single spatial mode from large-aperture devices. The lasers include an active medium that includes an array of quantum box ministacks, each ministack containing 2 to 5 vertically stacked, coupled quantum boxes.

Abstract: An intersubband quantum cascade laser structure includes multiple coupled laser stages, wherein each stage has a multilayer structure including an electron injector, an active region with at least one quantum well, and an electron reflector. Electrons injected from the injector into the active region at a high energy level relax to a lower energy level with the emission of a photon at, for example, mid-infrared wavelengths. The reflector reflects electrons at the higher energy level at which they were injected and transmits electrons from the lower energy level after emission of a photon. Multiple layers of semiconductor are formed on each side of the multistage structure to provide conduction across the device and to provide optical confinement of the photons emitted.

Abstract: A semiconductor laser is formed on a semiconductor substrate with an array of laterally spaced laser device elements each including a second order distributed feedback grating bounded by distributed Bragg reflector gratings. The device elements in which the distributed feedback grating and the distributed Bragg reflector gratings are formed have a lower effective index than the index of the interelement regions and are spaced so as to form an antiguided array.

Abstract: A semiconductor laser and light emitting device is defined. The device comprises an electron injector and an active region adjacent to the electron injector. The active region includes at least one deep quantum well with barrier layers adjacent to either side of the quantum well or wells such that electrons injected from the electron injector into a high energy level of the quantum well relax to a lower energy level with the emission of a photon and are transmitted out to a region beyond the last barrier layer of the active region. The electron injector includes quantum well layers. The bottom of each deep quantum well or wells in the active region is lower in energy than the bottoms of the quantum well layers in the electron injector. The device may further comprise at least two stages wherein each stage contains an electron injector and an active region.

Abstract: Semiconductor light emitting sources are formed to have a substrate, an active region layer having one or more quantum wells, optical confinement layers surrounding the active region layer, and a p-type cladding layer and an n-type cladding layer surrounding the confinement layers and the active region layer. At least one of the optical confinement layers has a region of doping therein that is formed to provide a built-in electric field in the confinement layer that is directed to cause drift of carriers toward the active region. The electric field increases the transport speed of the injected holes or electrons, thereby reducing the non-ohmic voltage drop and increasing the overall efficiency of the light emitting source.

Abstract: A semiconductor laser is formed on a semiconductor substrate with an array of laterally spaced laser device elements each including a second order distributed feedback grating bounded by distributed Bragg reflector gratings and a central phase shift in the distributed feedback grating. The device elements in which the distributed feedback grating and the distributed Bragg reflector gratings are formed have a lower effective index than the index of the interelement regions and are spaced so as to form an antiguided array. A two-dimensional semiconductor array laser may be formed of four or more of the semiconductor array devices arranged on the substrate to provide long range coherent coupling via traveling waves of light between the device elements.

Abstract: A semiconductor laser is formed on a semiconductor substrate with an array of laterally spaced laser device elements each including a second order distributed feedback grating bounded by distributed Bragg reflector gratings and a central phase shift in the distributed feedback grating. The device elements in which the distributed feedback grating and the distributed Bragg reflector gratings are formed have a lower effective index than the index of the interelement regions and are spaced so as to form an antiguided array. A two-dimensional semiconductor array laser may be formed of four or more of the semiconductor array devices arranged on the substrate to provide long range coherent coupling via traveling waves of light between the device elements.

Abstract: Semiconductor light emitting sources are formed to have a substrate, an active region layer having one or more quantum wells, optical confinement layers surrounding the active region layer, and a p-type cladding layer and an n-type cladding layer surrounding the confinement layers and the active region layer. At least one of the optical confinement layers has a region of doping therein that is formed to provide a built-in electric field in the confinement layer that is directed to cause drift of carriers toward the active region. The electric field increases the transport speed of the injected holes or electrons, thereby reducing the non-ohmic voltage drop and increasing the overall efficiency of the light emitting source.

Abstract: A surface emitting semiconductor laser capable of operating at high power levels and with high efficiency is formed to emit in a single far-field lobe in a single mode. The laser includes a semiconductor substrate and epitaxial structure including an active region layer and cladding layers. A distributed feedback grating is formed of periodically alternating grating elements to provide optical feedback as a second order grating for the effective wavelength of light generation from the active region. Surface emission in a single lobe pattern may be obtained by forming one edge face of the structure to be reflective and the other face to be antireflective. The semiconductor laser may also be formed to have a symmetric near-field pattern and single lobe surface emission utilizing a phase shift in the 2nd-order distributed feedback grating at its center and with antireflective edge faces.

Abstract: A resonant tunneling diode is produced in a gallium arsenide material system formed with barrier layers of AlGaAs with a quantum well layer of low band-gap material between them. The material of the well is selected to adjust the second energy level to the edge of the conduction band in GaAs, with a preferred quantum well layer formed of InGaAs. The resonant tunneling diode structure is grown by a metal organic chemical vapor deposition process on the surface of the nominally exact (100) GaAs substrate. Layers of doped GaAs may be formed on either side of the multilayer resonant tunneling diode structure, and spacer layers of GaAs may also be provided on either side of the barrier layers to reduce the intrinsic capacitance of the structure.

Abstract: High power edge emitting semiconductor lasers are formed to emit with very narrow spectral width at precisely selected wavelengths. An epitaxial structure is grown on a semiconductor substrate, e.g., GaAs, and includes an active region at which light emission occurs, upper and lower confinement layers and upper and lower cladding layers. A distributed feedback grating is formed in an aluminum free section of the upper confinement layer to act upon the light generated in the active region to produce lasing action and emission of light from an edge face of the semiconductor laser. Such devices are well suited to being formed to provide a wide stripe, e.g., in the range of 50 to 100 &mgr;m or more, and high power, in the 1 watt range, at wavelengths including visible wavelengths.

Abstract: A resonant tunneling diode is produced in a gallium arsenide material system formed with barrier layers of AlGaAs with a quantum well layer of low band-gap material between them. The material of the well is selected to adjust the second energy level to the edge of the conduction band in GaAs, with a preferred quantum well layer formed of InGaAs. The resonant tunneling diode structure is grown by a metal organic chemical vapor deposition process on the surface of the nominally exact (100) GaAs substrate. Layers of doped GaAs may be formed on either side of the multilayer resonant tunneling diode structure, and spacer layers of GaAs may also be provided on either side of the barrier layers to reduce the intrinsic capacitance of the structure.

Abstract: The semiconductor laser emitting light in the wavelength range of about 700 nm to 800 nm utilizes an aluminum-free active region layer. An epitaxial structure is grown on a GaAs or AlGaAs substrate and includes an active region layer, confinement layers adjacent the active region layer, and cladding layers adjacent the confinement layers. The active region layer comprises at least one compressively strained InGaAsP quantum well surrounded by transitional layers, with the composition and width of the active region selected to emit light at a selected wavelength, particularly between about 700 nm and 800 nm. High band-gap InGaAlP cladding layers and confinement layers may be utilized to suppress carrier leakage, and the epitaxial structure may be grown on a misoriented substrate to further reduce carrier leakage from the quantum well and improve the crystalline quality of the quantum well.