Wisconsin Alumni Research Foundation

Trw Limited

Other

Coherent, Inc.

Dan Botez

Luke J Mawst

Thomas L Earles

Jeremy Daniel Kirch

Dapeng P Xu

Christopher A Sigler

Michael Jansen

Thomas Francis Kuech

Jane J Yang

Thomas J Roth

Jae Cheol Shin

Charles A Zmudzinski

Ali R Mirabedini

Gary L Peterson

Steven Christopher Ruder

Jaroslava Z Wilcox

Peter S Zory, Jr

William W Simmons

Lawrence M Zinkiewicz

Gunawan Witjaksono

Iulian Basarab Petrescu-Prahova

Jerome Kent Wade

Abdulrahman Al-Muhanna

James G Lopez

Masoud J Kasraian

Chia-Fu Hsu

Single-mode quantum cascade semiconductor lasers are provided. The lasers comprise a laser element, the laser element comprising a quantum cascade active layer; an upper cladding layer over the quantum cascade active layer; and a lower cladding layer under the quantum cascade active layer, wherein the quantum cascade active layer, the upper cladding layer and the lower cladding layer define a guided optical mode. The quantum cascade active layer and the upper and lower cladding layers are shaped in the form of a ridge structure having a front face, a back face opposite the front face, and a lasing face through which laser emission exits the ridge structure, the ridge structure configured such that the laser emission has a single-lobe, far-field beam pattern from the ridge structure comprising certain sections, including tapered sections, collateral sections, or both.

High-power, single-spatial-mode quantum cascade lasers

A terahertz quantum cascade laser device is provided comprising a substrate having a top substrate surface, a bottom substrate surface, and an exit facet extending between the top substrate surface and the bottom substrate surface at an angle &#x3b8;. The device comprises a waveguide structure having a top surface, a bottom surface, a front facet extending between the top surface and the bottom surface and positioned proximate to the exit facet, and a back facet extending between the top surface and the bottom surface and oppositely facing the front facet. The waveguide structure comprises a quantum cascade laser structure configured to generate light comprising light of a first frequency &#x3c9;, light of a second frequency &#x3c9;, and light of a third frequency &#x3c9;, wherein &#x3c9;=&#x3c9;&#x2212;&#x3c9;; an upper cladding layer; and a lower cladding layer. The device comprises a distributed feedback grating layer configured to provide optical feedback for one or both of the light of the first frequency &#x3c9;and the light of the second frequency &#x3c9;and to produce lasing at one or both of the first frequency &#x3c9;and the second frequency &#x3c9;, thereby resulting in laser emission at the third frequency &#x3c9;at a Cherenkov angle &#x3b8;through the bottom surface of the waveguide structure into the substrate and exiting the substrate through the exit facet. The device comprises a high-reflectivity coating on the front facet of the waveguide structure.

Terahertz quantum cascade lasers

Methods for the fabrication of orientation-patterned semiconductor structures are provided. The structures are light-waveguiding structures for nonlinear frequency conversion. The structures are periodically poled semiconductor heterostructures comprising a series of material domains disposed in a periodically alternating arrangement along the optical propagation axis of the waveguide. The methods of fabricating the orientation-patterned structures utilize a series of surface planarization steps at intermediate stages of the heterostucture growth process to provide interlayer interfaces having extremely low roughnesses.

Fabrication of low-loss, light-waveguiding, orientation-patterned semiconductor structures

Methods for the fabrication of orientation-patterned semiconductor structures are provided. The structures are light-waveguiding structures for nonlinear frequency conversion. The structures are periodically poled semiconductor heterostructures comprising a series of material domains disposed in a periodically alternating arrangement along the optical propagation axis of the waveguide. The methods of fabricating the orientation-patterned structures utilize a series of surface planarization steps at intermediate stages of the heterostructure growth process to provide interlayer interfaces having extremely low roughnesses.

Semiconductor lasers comprise a substrate; an active layer configured to generate transverse magnetic (TM) polarized light under an electrical bias; an upper cladding layer; a lower cladding layer; and a distributed feedback (DFB) grating defined by the interface of a layer of metal and a layer of semiconductor under the layer of metal, the interface periodically corrugated in the longitudinal direction of the laser with a periodicity of &#x39b;=m&#x3bb;/(2n), wherein m&#x3e;1. The DFB grating is configured such that loss of one or more antisymmetric longitudinal modes of the laser structure via absorption to the DFB grating is sufficiently maximized so as to produce lasing of a symmetric longitudinal mode of the laser with laser emission characterized by a single-lobe beam along each direction defined by the grating diffraction orders corresponding to emission away from the plane of the grating.

Substrate-emitting transverse magnetic polarized laser employing a metal/semiconductor distributed feedback grating for symmetric-mode operation

Semiconductor structures for laser devices are provided. The semiconductor structures have a quantum cascade laser structure comprising an electron injector, an active region, and an electron extractor. The active region comprises an injection barrier, a multiquantum well structure, and an exit barrier. The multiquantum well structure can comprise a first barrier, a first quantum well, a second barrier, a second quantum well, and a third barrier. The energies of the first and second barrier are less than the energy of the third barrier. The energy difference between the energy of the second barrier and the energy of the third barrier can be greater than 150 meV and the ratio of the energy of the third barrier to the energy of the second barrier can be greater than 1.26.

Multiquantum well structures for suppression of electron leakage and reduction of threshold-current density in quantum cascade lasers

Semiconductor laser array devices capable of emitting mid- to long-wavelength infrared (i.e., 4-12 &#x3bc;m) radiation are provided. The devices include a quantum cascade laser (QCL) structure comprising one or more active cores; an optical confinement structure; a cladding structure, and a plurality of laterally-spaced trench regions extending transversely through the cladding and optical confinement structures, and partially into the QCL structure. The trench regions define a plurality of laterally-spaced interelement regions separated by element regions in the laser array device. The element regions are characterized by a non-uniform structure across their widths. As a result of this structural non-uniformity, array modes composed of coupled first-order lateral modes of the element regions are preferentially suppressed relative to array modes composed of coupled fundamental lateral modes of the element regions.

High-power quantum cascade lasers with active-photonic-crystal structure for single, in-phase mode operation

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.

High power, high efficiency quantum cascade lasers with reduced electron leakage

Semiconductor laser array devices capable of emitting mid- to long-wavelength infrared (i.e., 4-12 &#x3bc;m) radiation are provided. The devices include a quantum cascade laser (QCL) structure comprising one or more active cores; an optical confinement structure; a cladding structure; and a plurality of laterally-spaced trench regions extending transversely through the optical confinement and cladding structures, and partially into the QCL structure. The trench regions, each of which comprises a lower trench layer comprising a semi-insulating material and an upper trench layer comprising a material having a refractive index that is higher than that of the semi-insulating material, define a plurality of laterally-spaced interelement regions separated by element regions in the laser array device.

High-power quantum cascade lasers with active-photonic-crystal structure

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.

High efficiency intersubband semiconductor lasers

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. The stages are separated by semiconductor layers that allow the transfer of electrons from the active region of one stage to the electron injector of the next stage.

Intersubband mid-infrared electroluminescent semiconductor devices

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.

High coherent power, two-dimensional surface-emitting semiconductor diode array laser

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.

Intersubband quantum box stack lasers

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.

Growing community of inventors

Madison, WI, United States of America

Dan Botez