Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 51 for “"mode-matching"”.
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ADPATIVE MODE MATCHING UPGRADE FOR ADVANCED LIGO
… to optical losses generated by optical cavity mode mismatch. Optical losses due to mode mismatched Fabry-P´erot optical cavities can be reduced by the use of adaptive optics, wavefront sensors, and feedback control loops. Advanced LIGO currently uses adaptive hardware for alignment, but not for …
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Adaptive Mode Matching in Advanced LIGO and Beyond
… techniques for operating at higher power and mode matching Gaussian beams in the dual-recycled Michelson interferometer for the Advanced LIGO era and beyond. The first two chapters discuss the fundamentals of gravitational waves and the LIGO detector configurations. The third chapter …
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System architecture for mode-matching a MEMS gyroscope
… contains a resonator and an accelerometer, modeled as a two degree-of-freedom mass-spring system. When the resonant frequencies of each mode are matched, the mechanical output of the gyroscope is maximal. Feedback is used to match the two modes by automatically tuning the voltage on the …
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Mode Matching sensing in Frequency Dependent Squeezing Source for Advanced Virgo plus
… the squeezed vacuum beam and the resonance mode of the cavities. The mismatch can be modelled as a simple optical loss in the first approximation. If the beam shape of squeezed vacuum does not match the resonance mode, part of its amplitude is lost and replaced with the incoherent vacuum. …
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Mode-matching analysis for discontinuities in waveguide and application to a waveguide circular polarizer
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.
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Analysis and characterization of the integrated dielectric slab waveguide-wedge antenna using iterative mode-matching technique
… is presented. The method of solution involves modeling the wedge as a sequence of step discontinuities and using an iterative procedure to track forward and backward partial wave fields, expressed as modal expansions, to obtain the rigorous field solution. Radiation patterns of directive gain …
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Analysis of Waveguides Filled with Uniaxial Media and Metamaterials for Filter Applications using the Mode Matching Method
… waveguide class problems, but ultimately the Mode Matching Method (MMM) is chosen as the numerical analysis technique for this dissertation.</p> <p>An overview of waveguide theory and its application to the Mode Matching Method are presented. The Mode Matching Method is then used to analyze …
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Analysis of the Suspended H-Waveguide and Other Related Dielectric Waveguide Structures
… developed suspended H-waveguide based on the mode matching techniques is described. The derived eigenvalue equation for determining the propagation constant of this waveguide structure is very general and can be applied directly to other planar dielectric structures of rectangular cross …
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Towards Integrated Pixel Modelling
… the re-formulation and extension of traditional mode-matching methods, and the development of the software package SCATTER-TNG (S-TNG) to incorporate them. The foundations of this software are built on the legacy of mode matching routines developed by the Terahertz Group at Maynooth University. …
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Electromagnetic Analysis of Horn Antennas in the Terahertz region
… with the application of electromagnetic modelling techniques to the analysis of horn antenna characteristics over the terahertz range, 0.1 THz to 5 THz. The mode matching technique based on a scattering matrix approach to describe beam propagation in both the forward and backward …
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Static and Dynamic Properties of Vertical -Cavity Surface -Emitting Lasers
… the data to theoretical results using a vector mode-matching method which includes the fiber in the modelled structure. A novel method for estimating the linewidth enhancement factor in VCSELs is developed from the matching of theory and experiment. Two-mode competition in the VCSEL under …
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Electromagnetic and Quasi-Optical Analysis of Cavity Coupled Bolometers for Far-Infrared and Terahertz Receivers
… theoretical and computational techniques for the modelling of cavity coupled bolometric detectors for future millimetre wave and terahertz astronomical receivers. Hypersensitive bolometer based receivers will be required to answer current open questions in astronomy concerning star and planetary …
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High-power single-mode vertical-cavity surface-emitting lasers via impurity induced disordering
… the influence of IID on electrical, optical, and mode-control properties. A transfer matrix method (TMM) is developed to account for the diffusion of Group III atoms of the distributed Bragg reflectors (DBR) that comprise the VCSEL. In addition, a simple fiber model is used to design the …
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A High-Q Micromachined Quatrefoil Suspension Gyroscope
… modal coupling between two secondary elliptical modes of the ring via the Coriolis effect. These elliptical modes can be excited using a set of capacitive electrodes arranged proximal to the ring. The design provides good immunity to fabrication tolerances, achieving low frequency split between …
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The scattering of sound waves in two-dimensional ducts with discontinuities in height and material property
Eigen-mode matching techniques offer a versatile approach for solving acoustic scattering problems in ducts. However, until recently, these techniques have been restricted to problems in which the boundary conditions contain at most one derivative, that is, Neumann, Dirichlet or Robin's conditions. …
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A Method of Moments Solution of Stripline Discontinuity Problems
… In this application, the cutoff frequencies, model currents, and field distributions are found from a method of moments solution of an electric field integral equation. Finally, the scattering parameters of an arbitrarily shaped discontinuity in a stripline are found by solving an integral …
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Detector Improvements and Optimization to Advance Gravitational-wave Astronomy
… flexure-based piezo-deformable mirror for active mode-matching. Mode-matching losses limit improvements from squeezing as they distort the ground state of the squeezed beam. For broadband sensitivity improvements from frequency-dependent squeezing, it is critical to ensure low mode-mismatch …
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An Investigation of Modal Characteristics and Discontinuities in Printed Circuit Transmission Lines (Microstrip, Galerkin, Singular, Integral, Coupled-Mode)
… First, propagating and evanescent modes of a shielded microstrip are calculated using the spectral Galerkin technique. The characteristic impedance and field configurations of these modes are also calculated. These modes are then used in a mode matching technique, in order to …
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Investigation of Horn Optimisation, Simulation and Measurement Techniques, with Application to Integrating Cavity Based Pixel Design
… by placing further constraints on the various models that currently exist which serve to explain these processes, for example the various in ationary models. Significant efforts are being made to develop and characterise the technology required to realise these ambitions. Examples of missions …
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Finite Element Analysis Of Left-handed Waveguides
… waveguides and anomalous dispersion of modes is found. The discontinuity structure of a left-handed waveguide sandwiched between two conventional dielectric slab waveguides is analyzed using mode matching technique and the results are discussed based on the inherent nature of the …
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