84 results about "Quantum well laser" patented technology

A pair of undoped spacer layers are provided adjacent to, or near to, a single quantum well aluminum gallium nitride active region. In various exemplary embodiments, the undoped spacer layers are provided between the single quantum well aluminum gallium nitride active region and carrier confinement layers. The undoped spacer layers reduce the threshold current for the laser device and improve the output characteristics.

A pair of undoped spacer layers are provided adjacent to, or near to, a single quantum well aluminum gallium nitride active region. In various exemplary embodiments, the undoped spacer layers are provided between the single quantum well aluminum gallium nitride active region and carrier confinement layers. The undoped spacer layers reduce the threshold current for the laser device and improve the output characteristics.

In accordance with the present invention, GaAs-based optoelectronic devices have an active region that includes a well layer composed of a compressively-strained semiconductor that is free, or substantially free, of nitrogen disposed between two barrier layers composed of a nitrogen- and indium-containing semiconductor.

The invention discloses an energy band adjustable light-emitting diode (LED) quantum well structure and an epitaxial growth method thereof, wherein the energy band adjustable LED quantum well structure can improve radiative recombination efficiency in multiple quantum wells of an active area of an LED. The energy band adjustable LED quantum well structure comprises at least one quantum well potential well layer with component changing gradually, energy band control of a quantum well area can be achieved, electron hole wave function superposition in the active area of the quantum well can be improved, and radiative recombination efficiency of the LED quantum well area can be improved. The multiple quantum well structure can be applied to InGaN-based blue or green LEDs, improves internal quantum efficiency of active areas of the InGaN-based blue or green LEDs and further improves LED power and efficiency.

A circuit for generating a clock or sampling signal, the circuit including: a semiconductor quantum dot laser element including a region of quantum dots, wherein the region of quantum dots is characterized by an emission distribution having a half-width of at least about 10 meV; and drive circuitry connected to the quantum dot laser element for operating the quantum dot laser element as a mode-locked laser that outputs a periodic, uniformly spaced sequence of pulses, wherein the clock or sampling signal is derived from the sequence of pulses.

Exemplary embodiments provide tunable laser devices, methods for making the laser devices and methods for tuning the laser devices. The tunable laser devices can include an optically pumped semiconductor laser heterostructure, on which a distributed-feedback (DFB) laser grating having variable grating spacings (or chirps) can be formed. The optically pumped semiconductor laser heterostructure can be an optically pumped type-II quantum well laser structure. The emission wavelength of the tunable laser devices can be tuned by changing positions of the region illuminated by the pump laser and with respect to the chirped DFB grating. The disclosed laser devices and methods can provide tunable laser emission with a combination of narrow linewidth and high output power that can be used for remote sensing applications and / or spectroscopic applications across the entire mid infrared (IR) spectral region.

A circuit for generating a clock or sampling signal, the circuit including: a semiconductor quantum dot laser element including a region of quantum dots, wherein the region of quantum dots is characterized by an emission distribution having a half-width of at least about 10 meV; and drive circuitry connected to the quantum dot laser element for operating the quantum dot laser element as a mode-locked laser that outputs a periodic, uniformly spaced sequence of pulses, wherein the clock or sampling signal is derived from the sequence of pulses.

The present invention provides a single-chip white light LED device without fluorescent powder and with an adjustable color rendering index and a preparation method thereof. The device comprises: a substrate; a first epitaxial layer; n SiO2 layers with micro / nano holes in an array arrangement mode and arranged at the upper portion of the first epitaxial layer; n three-dimensional hexagonal trapezoid structures including InGaN / GaN quantum wells and located at the upper portions of the micro / nano holes; and quantum dot areas, each being located between each two three-dimensional hexagonal trapezoid structures. Through combination of luminous sources of quantum wells and quantum dots, the defects caused by fluorescent powder can be avoided, the advantages of combination of the quantum wells and the quantum dots can be fully utilized, and the luminous efficiency is improved. The components of In in the quantum wells are regulated to allow the sides of the obtained three-dimensional hexagonal trapezoid structures to emit blue light, the upper surfaces of the three-dimensional hexagonal trapezoid structures emit green light and / or yellow light being longer than the blue light in wavelength, the ratio of the mixed quantum dots in the gaps is changed, and therefore, the luminous wavelength and the intensity of the single-chip white light LED device without fluorescent powder and with an adjustable color rendering index are regulated, and a high color rendering index performance is achieved.

Method for making an InGaAs / GaAs quantum well laser (10) on a Silicon substrate (15.1). The method comprises the steps: Formation of a virtual Germanium substrate (15) on the Silicon substrate (15.1) by means of a low-energy plasma-enhanced chemical vapour deposition (LEPECVD). The virtual Germanium substrate (15) comprises a pure Germanium layer (15.3). Formation of a Gallium Arsenide structure on the virtual Germanium substrate (15) by means of a metal organic chemical vapour deposition process. The metal organic chemical vapour deposition process comprises the steps: formation of a first Gallium Arsenide layer (16) on the virtual Germanium substrate (15) at a first substrate temperature (Ts1), formation of a second Gallium Arsenide waveguide layer (17) at a second substrate temperature (Ts2), the second substrate temperature (Ts2) being higher than the first substrate temperature (Ts1) and the first Gallium Arsenide layer (16; 21) being thinner than the second Gallium Arsenide layer (17), formation of an active laser structure comprising a Gallium Arsenide waveguide layer (12) embedding a quantum well (11).

Controlling the number and type of quantum wells in a multilayer gain member of an external cavity surface emitting laser can provide output of light at more than one coherent optical wavelength. The number and type of layers in the multilayer mirror structure can provide a dual wavelength reflector.

In connection with an optical-electronic semiconductor device, improved photoluminescent output is provided at wavelengths approaching and beyond 1.3 μm. According to one aspect, a multiple quantum well strain compensated structure is formed using a GaInNAs-based quantum well laser diode with GaNAs-based barrier layers. By growing tensile-strained GaNAs barrier layers, a larger active region with multiple quantum wells can be formed increasing the optical gain of the device. In example implementations, both edge emitting laser devices and vertical cavity surface emitting laser (VCSEL) devices can be grown with at least several quantum wells, for example, nine quantum wells, and with room temperature emission approaching and beyond 1.3 μm.

Method for making an InGaAs / GaAs quantum well laser (10) on a Silicon substrate (15.1). The method comprises the steps:Formation of a virtual Germanium substrate (15) on the Silicon substrate (15.1) by means of a low-energy plasma-enhanced chemical vapourdeposition (LEPECVD). The virtual Germanium substrate (15) comprises a pure Germanium layer (15.3).Formation of a Gallium Arsenide structure on the virtual Germanium substrate (15) by means of a metal organic chemical vapour deposition process. The metal organic chemical vapour deposition process comprises the steps:formation of a first Gallium Arsenide layer (16) on the virtual Germanium substrate (15) at a first substrate temperature (Ts1),formation of a second Gallium Arsenide waveguide layer (17) at a second substrate temperature (Ts2), the second substrate temperature (Ts2) being higher than the first substrate temperature (Ts1) and the first Gallium Arsenide layer (16; 21) being thinner than the second Gallium Arsenide layer (17),formation of an active laser structure comprising a Gallium Arsenide waveguide layer (12) embedding a quantum well (11).

A quantum dot laser operates on a quantum dot ground-state optical transition. The laser has a broadband (preferably ≧15 nm) spectrum of emission and a high output power (preferably ≧100 mW). Special measures control the maximum useful pump level, the total number of quantum dots in the laser active region, the carrier relaxation to the quantum dot ground states, and the carrier excitation from the quantum dot ground states. In one embodiment, a spectrally-selective loss is introduced into the laser resonator in order to suppress lasing on a quantum dot excited-state optical transition, thereby increasing the bandwidth of the emission spectrum.

The invention discloses an InGaN / GaN quantum well laser, comprising a substrate and the following components sequentially arranged on the substrate: a low temperature GaN buffer layer, a high temperature n-type GaN layer and an n-type AlGaN light confinement layer; an n-type InGaN lower waveguide layer on the n-type AlGaN light confinement layer; an InGaN / GaN quantum well active region on the n-type InGaN lower waveguide layer; a u-type InGaN upper waveguide layer on the InGaN / GaN quantum well active region; a p-type AlGaN electron barrier layer on the u-type InGaN upper waveguide layer; a p-type AlGaN / GaN light confinement layer on the p-type AlGaN electron barrier layer; and a p-type GaN ohmic contact layer on the p-type AlGaN / GaN light confinement layer. The invention also discloses a manufacturing method for the InGaN / GaN quantum well laser. The invention adopts the InxGa1-XN of 1 to 2 single-atom layer thickness to be inserted into the cap layer so that the two-dimensional island-like surface of the InGaN quantum well surface becomes smooth, that the distribution of the In group becomes more uniform and that the subsequently formed GaN cap layer has a better quality in which the InGaN quantum well is not decomposed during the temperature rise and does not undergo thermal degradation during the subsequent high temperature growth of the p-type AlGaN / GaN light confinement layer.

This invention relates to a THz radiation chip of one micron wave length including: a substrate, a buffer layer prepared on the substrate, a Bragg reflection mirror set on the buffer layer to form a reflection mirror of high reflection rate and multiple quantum wells including multiple pairs of stranied compensated mono-quantum wells, in which, a low temperature growing technology is applied to process the multiple pairs of strained compensated quantum wells on the Bragg reflection mirror to absorb light and relax photocarriers, a pair of strip Ti-Au electrodes is made on the multiple quantum wells to play the role of offsetting current and strengthening the THz radiation.

The invention discloses atmosphere laser occultation signal generation and detection equipment and belongs to the technical field of atmospheric remote sensing measurement. In order to solve the problem that characteristic gas components and concentrations cannot be measured in the existing occultation signal generation system, the atmosphere laser occultation signal generation and detection equipment comprises a frequency and power stabilizing circuit, a quantum well laser array, a beam coupler, an optical fiber isolator, a power amplifier, an optical transmitting antenna, a first optical filter, a first collimating mirror, a first two-dimensional galvanometer, a second optical filter, a first coupling lens, a first beacon beam laser, a second coupling lens, a first imaging camera, an optical receiving antenna, a third optical filter, a second collimating mirror, a second two-dimensional galvanometer, a fourth optical filter, a third coupling lens, a second beacon beam laser, a fourth coupling lens, a second imaging camera, a third collimating mirror, a cylindrical mirror, a diffraction grating, an imaging reflector, an imaging CCD, a signal processing circuit and a data inversion module. The equipment has wide applications in the fields of atmospheric chemistry, global climate change, military battlefield aircraft monitoring and the like.

A micropost microcavity device has a maximum field intensity at the center of a high-index spacer as well as a small mode volume. The device has an approximately half-wavelength thick low-index spacer [400] sandwiched between two quarter wave stacks [410, 420]. The low-index spacer has a high-index subspacer layer [470] positioned at its center. The subspacer layer has a thickness smaller than a quarter wavelength. As a result, the electric field intensity remains a maximum at the center of the spacer where the high-index subspacer is positioned. A quantum dot or other active region [480] may be embedded within the subspacer [470]. The microcavity devices provide, for example, single photon sources, single dot lasers, low-threshold quantum dot or quantum well lasers, or devices for strong coupling between a single quantum dot and the cavity field which can be used as components of photonic integrated circuits, quantum computers, quantum networks, or quantum cryptographic systems.