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Showing 1 to 20 of 55 for “"Bragg Reflector"”.
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Bragg reflector geometries for colorimetric orientation and deformation sensing
… height and the combination of conformal and flat Bragg reflectors in order to identify suitable cavity designs. A MATLAB-based simulation environment was created to estimate the surfaces' intensity profile in monochromatic light and color chromaticity under any illumination source and incidence …
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Surface -Etched Distributed Bragg Reflector Lasers in Photonic Integrated Circuits
A high-power DBR laser array is also presented for use in spectral beam combining systems. The laser structure for this application is engineered for high-power applications. The engineering of the lateral optical guiding structure as well as the surface-etched grating is discussed.
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Bragg reflector thin-film resonators for miniature PCS bandpass filters
… is not limited by the AlN film quality. Several Bragg Reflector TFR devices were fabricated and tested. Sputtered SiO2 and AINOx were used as the low and high acoustic impedance materials respectively. The best devices have a bandwidth of approximately 3.6%, or 25MHz and a Q of 400. The low …
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Fabrication and measurements of surface-etched grating distributed Bragg reflector laser
… laser gain is relatively broad, so a distributed Bragg reflector (DBR) laser is used to make a narrow linewidth laser. The thesis discusses semiconductor lasers that use surface-etched DBR along with the physics of both the semiconductor and the DBR laser. The topics addressed are the fabrication …
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Swept-Frequency Sampled Grating Distributed Bragg Reflector Lasers Optimized for Optical Coherence Tomography Applications
… at a low cost. The sampled grating distributed Bragg reflector (SG-DBR) laser provides wide wavelength tuning range while exhibiting a wavelength switching speed that is among the fastest currently available. The SG-DBR laser is used to generate linear frequency ramps with high repetition rates. …
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Design and Characterization of Integrated Photonic Devices Fabricated Using Selective-Area Epitaxy and Distributed Bragg Reflector Surface Gratings
… in integrated photonic devices using distributed Bragg reflectors (DBRs). In this dissertation, ridge-waveguide DBR lasers with first-order surface gratings are investigated. These lasers exhibit low thresholds (6 mA), high slope efficiencies (0.46 W/A), and single-frequency operation with narrow …
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Investigation of porous alumina as a self-assembled diffractive element to facilitate light trapping in thin film silicon solar cells
… which incorporates a backside distributed Bragg reflector with a diffraction grating for large-angle diffraction. This study develops a simple and cost-effective fabrication method of using porous alumina as a self-assembled textured photonic crystal. Porous alumina is an attractive …
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Stabilization techniques and silicon-germanium saturable absorbers for high repetition rate mode-locked lasers
… of manufacturing a CMOS-compatible saturable Bragg reflector in the Si-SiO2-Ge materials system, enabling the monolithic integration of the absorber with the laser gain medium of future compact mode-locked lasers. A wafer-scale Si-SiO2 high reflector with 99.8% peak reflectance and an …
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Nonlinear optical frequency conversion of mode-locked all-solid-state lasers
… system that is mode-locked using a saturable Bragg reflector. Although the additive-pulsed mode-locked laser demonstrates higher peak power, it is observed to be less robust due to vibrational intolerance. Therefore, the saturable Bragg reflector mode-locked laser is chosen as the basis for …
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Design and fabrication of one-dimensional and two-dimensional photonic bandgap devices
… the realization of a wide-bandwidth distributed Bragg reflector ...
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Technological assessment of light-trapping technology for thin-film Si solar cell
… light trapping technology of Distributed Bragg Reflector (DBR) with Diffraction Grating (DG) and Anti-Reflection Coating (ARC) for thin film Si solar cell was analyzed from the technology, market, and implementation perspectives. Two applications were investigated. For monocrystalline thin …
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Vertical -Cavity Surface -Emitting Lasers Operating in Photonic Crystal Waveguide Defect Modes
… of etched circular holes in the top distributed Bragg reflector of a vertical cavity surface-emitting laser to achieve single mode operation with a simple fabrication process is carried out. A theoretical analysis of photonic crystals is conducted to design devices, and the accuracy of the …
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Red emitting photonic devices using InGaP/InGaAlP material system
… a quantum well active region and a distributed bragg reflector at the bottom to reduce loss of emitted light into the substrate. The first device emits at a wavelength of 650 nm and is intended to create a photonic crystal light emitting diode (PCLED). PCLEDs have been demonstrated to have …
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Narrow frequency-band laser with optical feedback
… with optical feedback. We use a distributed Bragg reflector (DBR) laser diode centered at the cesium D₂ transition wavelength, [gamma] = 852 nm. The linewidth of this diode is reduced by several orders of magnitude by means of optical feedback from an external cavity. The system is further …
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Optical manipulation of helium(2(3)S) atoms with a diode laser
… strained multiquantum well with a distributed Bragg reflector to insure single longitudinal mode operation. The laser has been frequency stabilized to less than 1 MHz/hr drift. The helium metastable atom beam is produced by electron impact and the polarization is measured using a Stern-Gerlach …
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Quantum dot polymer composite materials for light management in optoelectronic devices
… in the waveguide. Furthermore, a distributed Bragg reflector dramatically mitigates the negative impact of scattering in the waveguide, allowing efficient photon collection and concentration ratio. White-light LED is achieved by using a phosphor material to convert monochromatic light from a …
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Optical loss and high-speed modulation of vertical-cavity surface-emitting lasers
… impurity doping concentration in the distributed Bragg reflector (DBR) mirrors of the VCSEL on its maximum power, current threshold, and slope efficiency are examined. By optimizing the amount of impurity doping distributed in the mirrors, improved performance of VCSEL can be developed. The small …
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One-dimensional simulation of vertical-cavity surface-emitting lasers including energy transport
… simulation results for VCSELs with various Bragg reflector mirrors.
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Block copolymer photonic crystals : towards self-assembled active optical elements
… driven lasing and stimulus responsive tunable reflectors. In pursuing these primary objectives, control of thin film microdomain orientation and novel three-dimensional (3D) optical characterization of block copolymer photonic crystals have been also achieved, both of which can greatly help …
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RELATIVISTIC BACKWARD WAVE OSCILLATOR WITH A GAUSSIAN RADIATION PATTERN AND RELATED TECHNOLOGIES
… the microwave signal axially, a cavity resonator reflector or cutoff waveguide section are widely used to reflect the TM01 mode backward wave to a TM01 mode forward wave. To provide a HPM Gaussian-like TE11 wave beam, an X-band relativistic BWO (RBWO) is proposed that uses a Bragg reflector …
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