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 39 for “"coupled mode theory"”.
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Integrable semiconductor ring lasers and two-dimensional rectangular lattice distributed feedback lasers
… feedback lasers are proposed and analyzed by a coupled mode theory.
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Soliton Propagation in nonlinear optical fibers: theory and application
… optical fibers arc reviewed. A mathematical model of a nonlinear optical fiber is developed using a coupled-mode theory approach, and methods of solving nonlinear partial differential equations arc discussed. A detailed history of research in the field is given, and recommendations for future …
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Distributed Bragg Pulse Shapers for Terahertz Modulation and Ultrafast Communications
The operation of the DBPS is modeled using coupled-mode theory, and a simulation of the device is presented that accurately reproduces observed data. The simulation is used to model pulse shapers with ideal characteristics. The magnitude and speed of the electrically induced refractive index …
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Modeling of DFB surface emitting lasers and semiconductor laser arrays
Theoretical modeling of novel semiconductor laser systems, i.e., distributed-feedback (DFB) surface emitting lasers and semiconductor laser arrays, is presented. The DFB surface emitting lasers can produce stable single-mode outputs even under high bit-rate direct modulation and form …
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Programmable Liquid-Crystal-on-Silicon Photonic Integrated Circuits with Millions of Degrees of Freedom
… and explore the idea of a programmable Multi-Mode Interferometer using LCoS technology, enabling the performance of arbitrary unitary transformations. Future work will focus on developing robust simulations of coupled-mode theory with liquid crystals, paving the way for next-generation …
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An investigation of the perfectly matched layer for inhomogeneous media
… and the smoothness of the absorption profile via coupled-mode theory, and show how to obtain higher-order and even exponential vanishing of the reflection with absorber thickness.
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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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A study of periodic gratings in planar dielectric waveguides
… boundary perturbations is carried out using coupled-mode theory. Power reflection and transmission coefficients are calculated for single gratings as well as two gratings of the same period and depth but arbitrary lengths and separated by a specified distance. The spectral response is …
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Three-dimensional propagation and scattering around a conical seamount
… three-dimensional propagation and scattering model is developed based on the three-dimensional coupled mode theory for axisymmetric bathymetry. The three-dimensional coupled mode approach applied in this thesis is fundamentally identical to the one applied in earlier models, such as the one …
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Scattering design : absorption enhancement and frequency selective metasurfaces
… coherent effects) justify the use of a diffusion model as an upper estimation for the enhancement. This allows us to write an analytical formula for the maximum angle/frequency-averaged enhancement. We use this result to propose and quantify approaches to increase performance through careful …
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Passive components for dense optical integration based on high index-contrast
… filters that rely on symmetry and degeneracy of modes, low-loss right-angle bends, splitters, crossings based on transmission cavities, and fiber-chip couplers based on cascades of resonators or lensing mechanisms. Their operating principles are explained and an approximate analysis is obtained …
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Coupled-waveguide Fabry-Perot resonator
… narrow spectral width but lack the capability of mode discrimination. A new coupled-waveguide Fabry-Perot resonator made of two parallel waveguides with reflecting mirrors at the ends is proposed for application as narrowband tuned spectral filter in single-mode diode lasers and wavelength …
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Coupled mode reductions and rotating wave approximations in nonlinear equations
… this thesis, we investigate the applicability of coupled mode theory in the cubic-quintic nonlinear Schrodinger/Gross Pitaevskii (NLS/GP) equation with a linear double-well potential and study justifications of the rotating wave approximations in lattice systems. First, we study the long-time …
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Temperature and Spatial Hole Burning Effects in Semiconductor Lasers and Integrated Optical Devices
… and experimentally in both Fabry-Perot and index-coupled distributed-feedback lasers. The photon density profiles are calculated and compared with the carrier density profiles extracted from spontaneous emission measurements. The facet reflection coatings have a large impact on the spatial hole …
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Vlasov simulations of kinetic enhancement of Raman backscatter in laser fusion plasmas
… Landau damped in the regimes of interest, and coupled-mode theory predicts back-scattered SRS is a convective instability. Simulations in a finite length, homogeneous plasma show electron trapping drastically elevates the reflected light over convective gain values ("kinetic enhancement"). …
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Wavelength compensation in fused fiber couplers
… taper (FBT) couplers including both multimode and single-mode fiber couplers are studied in detail. In multimode fiber coupler operation, a novel theoretical model based on frustrated total internal reflection (FTIR) has been developed to effectively describe the power coupling and loss …
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A theoretical study into the fundamental design limits of devices based on one-and two-dimensional structured fibres
… losses on uniform gratings and of cladding mode losses on linearly chirped gratings have been studied by means of two extended versions of coupled-mode theory. The possibility of compensating the cladding mode losses acting on the chirped grating profile is also analysed. Considering the …
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All-fiber Spectral Filters based on LP01 - LP11 Mode Coupling and Applications in Wavelength Division Multiplexing and Dispersion Compensation
… networks. Spectral filters made of single-mode identical or dissimilar core parallel fibers provide 3-dB spectral widths on the order of 1 to 10 nm. A spectral filter made of single-mode and dual-mode fibers and operating based on coupling of power between LP01 and LP11 modes is proposed …
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Tailoring light with photonic crystal slabs : from directional emission to topological half charges
… features. First, we develop a general coupled-mode theory formalism to derive bounds on the asymmetric decay rates to top and bottom of a photonic crystal slab, for a resonance with arbitrary in-plane wavevector. We then employ this formalism to inversion symmetric structures, and show …
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Geometric manipulation of light : from nonlinear optics to invisibility cloaks
… harmonic generation or four-wave mixing using coupled-mode theory. Using this framework, we show there is a critical input power at which maximum frequency conversion is possible. We study in depth the case of third harmonic generation, its solutions, and their stability analysis. Based on the …
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