Abstract: Implementations and techniques for coupled asymmetric quantum confinement structures are generally disclosed.

Abstract: A quantum cascade laser is configured to include a semiconductor substrate, and an active layer that is provided on the substrate and has a cascade structure formed by alternately laminating emission layers and injection layers by multistage-laminating unit laminate structures each consisting of the quantum well emission layer and the injection layer, and generates light by intersubband transition in a quantum well structure. In a laser cavity structure for light with a predetermined wavelength generated in the active layer, a front reflection film with a reflectance of not less than 40% and not more than 99% for laser oscillation light is formed on the front end face that becomes a laser beam output surface, and a back reflection film with a reflectance higher than that of the front reflection film for the laser oscillation light is formed on the back end face.

Abstract: The present invention provides an applications-oriented nitride compound semiconductor substrate, and devices based on it, whose lattice constant can be tuned to closely match that of any nitride thin film or films deposited on it for specific electronic or optoelectronic device applications. Such application-oriented nitride substrates, which can be composed of ternary InxGa1-xN, AlyIn1-yN, AlzGa1-zN, or quaternary AlaInbGa1-a-bN alloy compounds, minimize lattice-mismatch-induced dislocations and defects between the epitaxial films and the substrate on which the device layers are grown, leading to substantially improved device performance.

Abstract: A laser diode and method for fabricating same, wherein the laser diode generally comprises an InGaN compliance layer on a GaN n-type contact layer and an AlGaN/GaN n-type strained super lattice (SLS) on the compliance layer. An n-type GaN separate confinement heterostructure (SCH) is on said n-type SLS and an InGaN multiple quantum well (MQW) active region is on the n-type SCH. A GaN p-type SCH on the MQW active region, an AlGaN/GaN p-type SLS is on the p-type SCH, and a p-type GaN contact layer is on the p-type SLS. The compliance layer has an In percentage that reduces strain between the n-type contact layer and the n-type SLS compared to a laser diode without the compliance layer. Accordingly, the n-type SLS can be grown with an increased Al percentage to increase the index of refraction. This along with other features allows for reduced threshold current and voltage operation.

Abstract: An interband cascade laser amplifier medium having an amplifier region (V) comprising a hole quantum film (1) comprising a first semiconductor material and an electron quantum film (2) comprising a second semiconductor material, an electron collector region (K) comprising at least one collector quantum film (4) comprising a third semiconductor material and separated by a first barrier layer (3), and an electron injector region (I) following the latter and comprising at least one injector quantum film (5) comprising a fourth semiconductor material and separated by a second barrier layer (3). The first semiconductor material of the hole quantum film (1) is a III-V compound semiconductor comprising at least four elements, at least two of the elements selected from Ga, In and Al, and at least two of the elements selected from As, Sb, P and N. The amplifier medium exhibits an efficient laser emission at wavelengths above 2.5 ?m.

Abstract: A laser module LM is provided with a quantum cascade laser 1, a tubular member 5, and an infrared detector 7. The tubular member 5 has a pair of opening ends 5a, 5b and is arranged so that one opening end 5a is opposed to a face 1b opposed to an emitting end face 1a of the quantum cascade laser 1. The infrared detector 7 is arranged so as to be opposed to the other opening end 5b of the tubular member 5. Light emitted from the face (rear end face) 1b opposed to the emitting end face (front end face) 1a of the quantum cascade laser 1 is guided inside the tubular member 5 to enter the infrared detector 7, and then is detected.

Abstract: A vertical external cavity surface emitting laser (VECSEL) structure includes a heterostructure and first and second reflectors. The heterostructure comprises an active region having one or more quantum well structures configured to emit radiation at a wavelength, ?lase, in response to pumping by an electron beam. One or more layers of the heterostructure may be doped. The active region is disposed between the first reflector and the second reflector and is spaced apart from the first reflector by an external cavity. An electron beam source is configured to generate the electron beam directed toward the active region. At least one electrical contact is electrically coupled to the heterostructure and is configured to provide a current path between the heterostructure and ground.

Abstract: A short optical pulse generator which includes an optical pulse generation portion that has a quantum well structure and generates an optical pulse, a frequency chirp portion that has a quantum well structure and chirps a frequency of the optical pulse, and a group velocity dispersion portion that includes a plurality of optical waveguides disposed in a mode coupling distance and which causes a group velocity difference corresponding to a wavelength in the optical pulse of which the frequency is chirped.

Abstract: A device including one or more layers with lateral regions configured to facilitate the transmission of radiation through the layer and lateral regions configured to facilitate current flow through the layer is provided. The layer can comprise a short period superlattice, which includes barriers alternating with wells. In this case, the barriers can include both transparent regions, which are configured to reduce an amount of radiation that is absorbed in the layer, and higher conductive regions, which are configured to keep the voltage drop across the layer within a desired range.

Abstract: A semiconductor device includes a substrate supporting a plurality of layers that include at least one modulation doped quantum well (QW) structure offset from a quantum dot in quantum well (QD-in-QW) structure. The modulation doped QW structure includes a charge sheet spaced from at least one QW by a spacer layer. The QD-in-QW structure has QDs embedded in one or more QWs. The QD-in-QW structure can include at least one template/emission substructure pair separated by a barrier layer, the template substructure having smaller size QDs than the emission substructure. A plurality of QD-in-QW structures can be provided to support the processing (emission, absorption, amplification) of electromagnetic radiation of different characteristic wavelengths (such as optical wavelengths in range from 1300 nm to 1550 nm).

Abstract: The present invention relates generally to highly power-efficient quantum cascade sources, such as highly power-efficient quantum cascade lasers having ultra-strong coupling between injector and active regions which may be configured to provide broadband quantum cascade lasers.

Abstract: A semiconductor laser includes a columnar lamination structure including a first multi-layer reflection mirror, a first spacer layer, an AlxGayIn1-x-yP (where 0?x<1 and 0<y<1) based active layer, a second spacer layer, a second multi-layer reflection mirror, and a lateral mode adjusting layer on a substrate in this order from the substrate and including a current narrowing layer. The current narrowing layer includes an unoxidized region in an in-plane central region and a circular oxidized region in the circumference of the unoxidized region. The later mode adjusting layer includes a high reflection region to correspond to the unoxidized region and a circular low reflection region in the circumference of the high reflection region. On the assumption that a diameter of the unoxidized region is Dox and a diameter of the high reflection region is Dhr, the diameters Dox and Dhr satisfy an expression of 0.8<Dhr/Dox<1.5.

Abstract: A semiconductor device is disclosed comprising: a substrate having a surface comprising germanium; a layer of gallium on said surface; and a layer of gallium arsenide on the gallium covered surface. The semiconductor heterostructure of gallium arsenide on germanium is fabricated by the steps of: protecting by a shutter a surface comprising germanium in an environment having a partial pressure of arsenic less than 10?8torr; epitaxially growing a layer of gallium on the said surface immediately after exposure of said surface; and epitaxially growing a layer of gallium arsenide on the gallium covered surface.

Abstract: Photonic integrated circuits on silicon are disclosed. By bonding a wafer of compound semiconductor material as an active region to silicon and removing the substrate, the lasers, amplifiers, modulators, and other devices can be processed using standard photolithographic techniques on the silicon substrate. A silicon laser intermixed integrated device in accordance with one or more embodiments of the present invention comprises a silicon-on-insulator substrate, comprising at least one waveguide in a top surface, and a compound semiconductor substrate comprising a gain layer, the compound semiconductor substrate being subjected to a quantum well intermixing process, wherein the upper surface of the compound semiconductor substrate is bonded to the top surface of the silicon-on-insulator substrate.

Abstract: A quantum cascade semiconductor laser includes a n-type semiconductor substrate, the substrate having a main surface; a mesa waveguide disposed on the substrate, the mesa waveguide including a core layer and an n-type upper cladding layer disposed on the core layer; a first semiconductor layer disposed on a side surface of the mesa waveguide and the main surface of the substrate, the first semiconductor layer being in contact with the side surface of the mesa waveguide; and a second semiconductor layer disposed on the first semiconductor layer. The first semiconductor layer and the second semiconductor layer constitute a burying region embedding the side surfaces of the mesa waveguide. The first semiconductor layer is formed of at least one of a semi-insulating semiconductor and a p-type semiconductor. In addition, the second semiconductor layer is formed of an n-type semiconductor.

Abstract: An embodiment of semiconductor laser comprising: (a) a GaN, AlGaN, InGaN, or AlN substrate; (b) an n-doped cladding layer situated over the substrate; (c) a p-doped cladding layer situated over the n-doped; (d) at least one active layer situated between the n-doped and the p-doped cladding layer, and at least one of said cladding layers comprises a superstructure structure of AlInGaN/GaN, AlInGaN/AlGaN, AlInGaN//InGaN or AlInGaN/AlN with the composition such that the total of lattice mismatch strain of the whole structure does not exceed 40 nm %.

Abstract: Laser diodes and methods of fabricating laser diodes are disclosed. A laser diode includes a substrate including (Al,In)GaN, an n-side cladding layer including (Al,In)GaN having an n-type conductivity, an n-side waveguide layer including (Al,In)GaN having an n-type conductivity, an active region, a p-side waveguide layer including (Al,In)GaN having a p-type conductivity, a p-side cladding layer including (Al,In)GaN having a p-type conductivity, and a laser cavity formed by cleaved facets. The substrate includes a crystal structure having a surface plane orientation within about 10 degrees of a 20 23 or a 20 23 crystallographic plane orientation. The laser cavity is formed by cleaved facets that have an orientation corresponding to a nonpolar plane of the crystal structure of the substrate.

Abstract: Described are embodiments of apparatuses and systems including a hybrid laser including anti-resonant waveguides, and methods for making such apparatuses and systems. A hybrid laser apparatus may include a first semiconductor region including an active region of one or more layers of semiconductor materials from group III, group IV, or group V semiconductor, and a second semiconductor region coupled with the first semiconductor region and having an optical waveguide, a first trench disposed on a first side of the optical waveguide, and a second trench disposed on a second side, opposite the first side, of the optical waveguide. Other embodiments may be described and/or claimed.

Abstract: This provides a semiconductor laser device of a high light output efficiency, which is high in current confinement effect, small in leak current, and favorable in temperature property, and indicates a low threshold current, and can effectively confine laser light to a stripe region, and is favorable in beam profile. This semiconductor laser device includes the laminated structure of an n-AlInP clad layer, a superlattice active layer section, a p-AlInP first clad layer, a GaInP etching stop layer are formed, and on top of that, there are a p-AlInP second clad layer, a GaInP protective layer and a p-GaAs contact layer, which are processed into a stripe-shaped ridge. A p-side electrode is directly coated and formed on the etching stop layer of ridge top surface.

Abstract: A nitride semiconductor laser diode comprises a substrate; an n-side nitride semiconductor layer containing an n-type impurity and disposed on the substrate; an active layer having a light emitting layer including InxAlyGa1?x?yN (0<x<1, 0?y<1, and 0<x+y<1) and disposed on the n-side nitride semiconductor layer; and a p-side nitride semiconductor layer containing a p-type impurity and disposed on the active layer. The lasing wavelength of the nitride semiconductor laser diode is 500 nm or greater.

Abstract: A first cladding layer is formed above a substrate. An active layer is formed above the first cladding layer. An optical confinement layer is formed above the active layer. A pair of band-like current block layers is formed above the optical confinement layer and opposed to each other through an opening extending in a first direction. A second cladding layer is formed on the current block layers and the optical confinement layer. A contact layer is formed above the second cladding layer. A mesa portion is formed by being sandwiched between a pair of groove portions. The current block layers and the opening are included in the mesa portion, and an end of each current block layer on an opposite side to the opening and a side wall of the mesa portion are spaced apart by a predetermined value or more in a second direction.

Abstract: Implementations and techniques for coupled asymmetric quantum confinement structures are generally disclosed.

Abstract: Concatenated distributed feedback lasers having novel waveguides are disclosed. The waveguides allow for coupling of the laser beam between active and passive waveguide structures and improved device design and output efficiency. Methods of making along with methods of using such devices are also disclosed.

Abstract: A semiconductor stack includes a semiconductor DBR (Distributed Bragg Reflector) formed on a substrate, and a resonator formed on the semiconductor DBR laminating wide-band semiconductor layers and active layers alternately. Each of the active layers includes MQWs (Multiple Quantum Wells) and two spacer layers formed one on each surface of the MQWs. The MQWs are formed by laminating barrier layers and quantum well layers alternately. There are n layers of the wide-band semiconductor layer formed, and a band gap Egm of an m-th wide-band semiconductor layer counting from the substrate and a band gap Egm-1 of an m?1-th wide-band semiconductor layer counting from the substrate satisfy Egm-1<Egm where n and m are integers greater than or equal to 2, and 1<m?n.

Abstract: Multi-surface emitting mid-IR multiwavelength distributed-feedback quantum cascade ring lasers laid out in a concentric circle are disclosed. The lasers utilize quantum cascade core designs to produce optical gain in the mid-infrared region and may generate several wavelengths simultaneously or sequentially. Methods of making along with methods of using such devices are also disclosed.

Abstract: A nitride semiconductor laser diode includes a substrate, an n-side nitride semiconductor layer formed on the substrate, an active layer formed on the n-side nitride semiconductor layer and having a light emitting layer including InxAlyGa1-x-yN (0<x<1, 0 y<1, 0<x+y<1), and a p-side nitride semiconductor layer formed on the active layer.

Abstract: A quantum cascade laser and its method of fabrication are provided. The quantum cascade laser comprises one or more p-type electrical isolation regions and a plurality of electrically isolated laser sections extending along a waveguide axis of the laser. An active waveguide core is sandwiched between upper and lower n-type cladding layers and the active core and the upper and lower n-type cladding layers extend through the electrically isolated laser sections of the quantum cascade laser. A portion of the upper n-type cladding layer comprises sufficient p-type dopant to have become p-type and to have become an electrical isolation region, which extends across at least a part of the thickness upper n-type cladding layer along a projection separating the sections of the quantum cascade laser.

Abstract: A silicon vertical cavity laser with in-plane coupling comprises wafer bonding an active III-V semiconductor material above a grating coupler made on a silicon-on-insulator (SOI) wafer. This bonding does not require any alignment, since all silicon processing can be done before bonding, and all III-V processing can be done after bonding. The grating coupler acts to couple the vertically emitted light from the hybrid vertical cavity into a silicon waveguide formed on an SOI wafer.

Abstract: Embodiments of a method comprising guiding an optical mode with an optical waveguide disposed in silicon, overlapping both the optical waveguide and an active semiconductor material evanescently coupled to the optical waveguide with the optical mode guided through the optical waveguide, electrically pumping the active semiconductor material to inject current directed through the active semiconductor material and through the optical mode, and generating light in the active semiconductor material in response to the injected current. Other embodiments are disclosed and claimed.

Abstract: A semiconductor laser includes: a stacked body having an active layer including a quantum well layer, the active layer having a cascade structure including a first region capable of emitting infrared laser light with a wavelength of not less than 12 ?m and not more than 18 ?m by an intersubband optical transition of the quantum well layer and a second region capable of relaxing energy of a carrier alternately stacked, the stacked body having a ridge waveguide and being capable of emitting the infrared laser light; and a dielectric layer provided so as to sandwich both sides of at least part of side surfaces of the stacked body, a wavelength at which a transmittance of the dielectric layer decreases to 50% being 16 ?m or more, the dielectric layer having a refractive index lower than refractive indices of all layers constituting the active layer.

Abstract: A quantum cascade laser includes a substrate having a conductivity type, substrate having a first region, a second region, and a third region; a semiconductor lamination provided on a principal surface of the substrate, the semiconductor lamination including a mesa stripe section provided on the second region, an upper cladding layer having the same conductivity type as the substrate, a first burying layer, and a second burying layer, the mesa stripe section including a core layer; and an electrode provided on the semiconductor lamination. The first and second burying layers are provided on the first and third regions and on both side faces of the mesa stripe section. The upper cladding layer is provided on the mesa stripe section, the first burying layer, and the second burying layer. The first and second burying layers include a first and second semi-insulating semiconductor regions comprised of a semi-insulating semiconductor material.

Abstract: A broadband, integrated quantum cascade laser is disclosed, comprising ridge waveguide quantum cascade lasers formed by applying standard semiconductor process techniques to a monolithic structure of alternating layers of claddings and active region layers. The resulting ridge waveguide quantum cascade lasers may be individually controlled by independent voltage potentials, resulting in control of the overall spectrum of the integrated quantum cascade laser source. Other embodiments are described and claimed.

Abstract: An (Al,In,B,Ga)N based device including a plurality of (Al,In,B,Ga)N layers overlying a semi-polar or non-polar GaN substrate, wherein the (Al,In,B,Ga)N layers include at least a defected layer, a blocking layer, and an active region, the blocking layer is between the active region and the defected layer of the device, and the blocking layer has a larger band gap than surrounding layers to prevent carriers from escaping the active region to the defected layer. One or more (AlInGaN) device layers are above and/or below the (Al,In,B,Ga)N layers. Also described is a nonpolar or semipolar (Al,In,B,Ga)N based optoelectronic device including at least an active region, wherein stress relaxation (Misfit Dislocation formation) is at heterointerfaces above and/or below the active region.

Abstract: An optical device having a structured active region configured for one or more selected wavelengths of light emissions.

Abstract: An LED semiconductor body includes a semiconductor layer sequence which comprises a quantum structure which is intended to produce radiation and comprises at least one quantum layer and at least one barrier layer, wherein the quantum layer and the barrier layer are strained with mutually opposite mathematical signs.

Abstract: Optical devices having a structured active region configured for selected wavelengths of light emissions are disclosed.

Abstract: A light emitting system is disclosed. The system comprises an active region having a stack of bilayer quantum well structures separated from each other by barrier layers. Each bilayer quantum well structure is formed of a first layer made of a first semiconductor alloy for electron confinement and a second layer made of a second semiconductor alloy for hole confinement, wherein a thickness and composition of each layer is such that a characteristic hole confinement energy of the bilayer quantum well structure is at least 200 meV.

Abstract: A Vertical Cavity Surface Emitting Laser (VCSEL) capable of providing high output of fundamental transverse mode while preventing oscillation of high-order transverse mode is provided. The VCSEL includes a semiconductor layer including an active layer and a current confinement layer, and a transverse mode adjustment section formed on the semiconductor layer. The current confinement layer has a current injection region and a current confinement region. The transverse mode adjustment section has a high reflectance area and a low reflectance area. The high reflectance area is formed in a region including a first opposed region opposing to a center point of the current injection region. A center point of the high reflectance area is arranged in a region different from the first opposed region. The low reflectance area is formed in a region where the high reflectance area is not formed, in an opposed region opposing to the current injection region.

Abstract: An active zone for a light emission system including a series of layers at least a portion of which consists of antimony semiconductors III-V. The layers are arranged to form at least one quantum well surrounded by barriers for generating a light emission. The active zone also includes at least one layer forming an intermediate barrier arranged relative to the quantum well to form at least two quantum sub-wells coupled with each other. A heterostructure including at least one optical confinement layer surrounding at least one active zone; a laser emission system including one heterostructure deposited onto a substrate; and the use of an active zone for emitting a light beam having a wavelength of 1.55 ?m are disclosed.

Abstract: According to the concepts of the present disclosure, laser diode waveguide configurations are contemplated where the use of Al in the waveguide layers of the laser is presented in the form of InGaN/Al(In)GaN waveguiding superstructure comprising optical confining wells (InGaN) and strain compensating barriers (Al(In)GaN). The composition of the optical confining wells is chosen such that they provide strong optical confinement, even in the presence of the Al(In)GaN strain compensating barriers, but do not absorb lasing emission. The composition of the strain compensating barriers is chosen such that the Al(In)GaN exhibits tensile strain that compensates for the compressive strain of InGaN optical confinement wells but does not hinder the optical confinement.

Abstract: A semiconductor laser device generates blue-violet light with an emission wavelength of 400 to 410 nm. The device includes an n-type group III nitride semiconductor layer, an active layer laminated on the n-type semiconductor layer and having an InGaN quantum well layer, a p-type group III nitride semiconductor layer laminated on the active layer, and a transparent electrode contacting the p-type semiconductor layer and serving as a clad. The n-type semiconductor layer includes an n-type clad layer and an n-type guide layer disposed between the clad layer and the active layer. The guide layer includes a superlattice layer in which an InGaN layer and an AlxGa1-xN layer (0?x<1) are laminated periodically, the superlattice layer contacting the active layer and having an average refractive index of 2.6 or lower. The In composition of the InGaN layer is lower than that of the InGaN quantum well layer.

Abstract: A GaN edge emitting laser is provided comprising a semi-polar GaN substrate, an active region, N-side and P-side waveguiding layers, and N-type and P-type cladding layers. The GaN substrate defines a 20 21 crystal growth plane and a glide plane. The N-side and P-side waveguiding layers comprise a GaInN/GaN or GaInN/GaInN superlattice (SL) waveguiding layers. The SL layers of the N-side and P-side SL waveguiding layers have layer thicknesses between approximately 1 nm and 5 nm that are optimized for waveguide planarity. In another embodiments, planarization is enhanced by ensuring that the N-side and P-side GaN-based waveguiding layers are grown at a growth rate that exceeds approximately 0.09 nm/s, regardless of whether the N-side and P-side GaN-based waveguiding layers are provided as a GaInN/GaN SL, GaInN/GaInN SL or as bulk layers. In further embodiments, planarization is enhanced by selecting optimal SL layer thicknesses and growth rates.

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: A first cladding layer is formed above a substrate. An active layer is formed above the first cladding layer. An optical confinement layer is formed above the active layer. A pair of band-like current block layers is formed above the optical confinement layer and opposed to each other through an opening extending in a first direction. A second cladding layer is formed on the current block layers and the optical confinement layer. A contact layer is formed above the second cladding layer. A mesa portion is formed by being sandwiched between a pair of groove portions. The current block layers and the opening are included in the mesa portion, and an end of each current block layer on an opposite side to the opening and a side wall of the mesa portion are spaced apart by a predetermined value or more in a second direction.

Abstract: An improved optical device. The device has a gallium nitride substrate member comprising indium entities, gallium entities, and nitrogen entities. In one or more embodiments, the gallium nitride substrate member has an indium content ranging from about 1 to about 50% in weight. Preferably, the gallium nitride substrate member has a semipolar crystalline surface region or a non-polar crystalline surface region. The device has an epitaxially formed laser stripe region comprising an indium content ranging from about 1 to about 50% and formed overlying a portion of the semipolar crystalline orientation surface region or the non-polar crystalline surface region. The laser stripe region is characterized by a cavity orientation in a predefined direction according to a specific embodiment.

Abstract: Electrically pumped mid-IR semiconductor lasers that are operable at room temperature and possess a range of tunability up to 1100 nm, which constitutes a revolutionary (1-2 orders of magnitude) improvement in the range of tunability over existing semiconductor laser technology utilizing Doped quantum confined host material (DQCH) with characteristic spatial dimension of the confinement tuned to enable the overlap of the discrete levels of the host and impurity ions and efficient energy transfer from the separated host carriers to the impurity, wherein: said DQCH material has the formula TM:MeZ and/or MeX2Z4, wherein Me is selected from the group consisting of Zn, Cd, Ca, Mg, Sr, Ba, Hg, Pb, Cu, Al, Ga, In; Z is selected from the group consisting of S, Se, Te, O, N, P, As, Sb and their mixtures; X being selected from the group consisting of Ga, In, and Al; and TM is selected from the group consisting from V, Cr, Mn, Fe, Co, and Ni.

Abstract: A nitride semiconductor laser diode includes a substrate, an n-side nitride semiconductor layer formed on the substrate, an active layer formed on the n-side nitride semiconductor layer and having a light emitting layer including InxAlyGa1?x?yN (0<x<1, 0 y<1, 0<x+y<1), and a p-side nitride semiconductor layer formed on the active layer.

Abstract: A method of generating a photoluminescence map for an indium gallium nitride (InGaN) well can include presenting data on a pixel by pixel basis. The data can be generated as a function of emission wavelength, line width of emission, polarization of emission, and intensity of emission. The data can also be generated as a function of excitation polarization and polarization angle orientation with respect to film crystalline axes of the InGaN well. The data can also be generated as a function of multiple wavelengths of light to generate the photoluminescence map. The photoluminescence maps can be correlated to device internal quantum efficiency as measured in test devices. The resulting correlation maps can serve as line monitors of indium rich InGaN wafers used for green LEDs.

Abstract: A GaN edge emitting laser is provided comprising a semi-polar GaN substrate, an active region, an N-side waveguiding layer, a P-side waveguiding layer, an N-type cladding layer, and a P-type cladding layer. The GaN substrate defines a 20 21 crystal growth plane and a glide plane. The N-side and P-side waveguiding layers comprise a GaInN/GaN or GaInN/GaInN superlattice (SL) waveguiding layers. The superlattice layers of the N-side and P-side SL waveguiding layers define respective layer thicknesses that are optimized for waveguide planarity, the layer thicknesses being between approximately 1 nm and approximately 5 nm. In accordance with another embodiment of the present disclosure, planarization can be enhanced by ensuring that the N-side and P-side GaN-based waveguiding layers are grown at a growth rate that exceeds approximately 0.09 nm/s, regardless of whether the N-side and P-side GaN-based waveguiding layers are provided as a GaInN/GaN or GaInN/GaInN SL or as bulk waveguiding layers.

Abstract: The present invention is directed to the integration of a quantum cascade laser with a hollow waveguide on a chip to improve both the beam pattern and manufacturability. By coupling the QCL output into a single-mode rectangular waveguide the radiation mode structure can be known and the propagation, manipulation, and broadcast of the QCL radiation can then be entirely controlled by well-established rectangular waveguide techniques. By controlling the impedance of the interface, enhanced functions, such as creating amplifiers, efficient coupling to external cavities, and increasing power output from metal-metal THz QCLs, are also enabled.