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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 23 for “"index profile"”.
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Optical waveguide analysis using transmission lines
… Critical fibre properties such as mode field profiles, single-mode propagation conditions and dispersion characteristics can all be related to the optical fibre refractive index profiles. For this reason, it is of fundamental importance to be able to determine the optical fibre refractive …
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Application of electroabsorption in a semiconductor laser for electromagnetic field sensing
… a single quantum well and a steplike waveguiding index profile has demonstrated efficient modulation when operated as a light absorber rather than as an emitter.
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Theoretical and numerical studies of wave propagation and scattering in inhomogeneous media
… inhomogeneous medium with the linear refractive index profile is obtained. The technique is extended to treat the three-dimensional and range-dependent media with or without turning points. Two analytical expressions of the Green's functions are also obtained for such media. For a line source in …
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Development of "Core-Suction" Technique for Fabrication of Highly Doped Fibers for Optical Amplification and Characterization of Optical Fibers for Raman Amplification
… fabricated fibers were measured for refractive index profile, loss spectrum and spontaneous Raman spectra. Elemental analysis of the fiber samples was also performed using an electron microprobe. Erbium doped fiber amplifiers (EDFAs) were setup using 30 cm, 5cm and 1 cm lengths of fabricated …
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Realization of a 3D gradient index medium in porous silicon
… porosification, the material’s refractive index is defined by modulating the current density along the etch direction to change the porosity in either periodic or continuous fashion, making PSi an excellent materials platform for a variety of photonic and gradient refractive index (GRIN) …
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New optical fibre based technologies and their application in highly nonlinear systems
… designs, a multi-ring cladding and a simpler W-index profile, are characterised. The measurements confirm the advantages of the all-solid designs over the holey structures and reveal the possibility to achieve simultaneously a high nonlinear coefficient and a novel dispersion profile in such …
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Tapered waveguide lasers
… indicating a need to control the refractive index profile to maximise the overlap of the multimode-pump and single-mode laser. Field-assisted ion exchange is therefore investigated to improve the overlap of the diode-pump and laser modes in a tapered waveguide. Waveguides produced by this …
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Linear Optical Thin Films Formed by Electrostatic Self-Assembly
… and their optical parameters -- refractive index and average thickness for individual bilayer -- are investigated to provide a basis for the in-depth design of optical filters. High performance dielectric stack filters and narrowband and wideband antireflection coatings are designed using …
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Advanced waveguides for high power optical fibre sources
… emission from weaker bands in conventional step-index waveguides. For efficient emission and laser operation on the weaker emission bands, it is necessary to suppress unwanted stimulated emission on the strong transitions by preventing power from building up at the unwanted wavelengths. Discrete …
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A Data-Driven Approach to Improve Optical Fiber Manufacturing: Focus on Core Deposition
… challenges associated with insuring refractive index profile precision and glass purity. Starting with unsupervised learning, process by process, we applied linear and non linear dimensionality reduction algorithms (PCA and t-sne) to features matrices created from time series data and have been …
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Advanced fibre Bragg grating structures: design and application
… of high-quality reflection and time-delay profiles. Another product of the high flexibility provided by the developed fabrication technique have led to demonstrations of superstructured Bragg gratings for a number of exciting applications such as multiple-channel filters obtained through a …
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Design and fabrication of micro- and nano- dielectric structures for imaging and focusing at optical frequencies
… frequencies due to its specific refractive index profile. With the high flexibility of gradient effective index design with the " aperiodic" dielectric nanostructures, along with the design method using Hamiltonian Optics investigated in this research, the Luneburg lens was designed, …
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Modulation of coherently coupled surface-emitting laser arrays: analysis and applications
… bias conditions are leveraged to control array index profile and coupling phase, is developed to achieve coherently coupled operation of the phased VCSEL arrays reproducibly with high yield. An experimental study on the modulation characteristics and locking range dynamics of coherently coupled …
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Band edge lasing in chiral nematic liquid crystals
… Accurate descriptions of the refractive index profile of the liquid crystal and perovskite are developed and included in mathematical modelling, in addition to descriptions of the wavelength-dependent gain of a laser dye and perovskite. Suggestions for developing this modelling are made, …
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Low Nonlinearity Optical Fibers for Broadband and Long-Distance Communications
… haul applications is presented. The refractive index profiles of these fibers assume a depressed-core multi-clad geometry in order to achieve effective-areas much larger than those in conventional optical fibers. A systematic approach for designing large effective-area dispersion-shifted fibers, …
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Beiträge zur Dispersionskompensation basierend auf der Modenkonversion in höhere Moden und der Ausbreitung dieser Moden in Lichtwellenleitern
… with an arbitrary, rotation-symmetric refractive index profile is shown (chapter 3). A converter from the fundamental mode and back is needed in order to exploit the propagation properties of a higher order mode (HOM). In this work long-period gratings (LPG) were considered as mode converters …
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Polymer waveguide based optical interconnects for high-speed on-board communications
… model is developed using the measured refractive index profile and good agreement with the above experimental results is found. The effects of graded refractive index profiles on the performance of waveguide components (bends, crossings) are also investigated, demonstrating that appropriate …
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Analysis and design of broadband single-mode multi-clad fibers
… the dispersion-flattened single-mode fiber index profile with respect to: (1) minimum dispersion, (2) the wavelengths of zero-dispersion, (3) maximum width of dispersion-flattened window, (4) maximum layer index difference less than 0.8%, and (5) layer thickness larger than 3.5 μm. The …
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Novel methods for recording and reconstructing images in digital holographic microscopy
… morphology in terms of thickness or refractive index. Quantitative phase imaging refers to a set of emerging methods with the potential to provide quantitative real-time measurement of the phase delay introduced by the specimen with nanometric accuracy and with the same spatial resolution …
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Tunable Liquid Crystal Photonic Devices
… spatial light modulator. Different gradient profiles are obtained by using different photomasks. The nanoscale LC droplets are randomly distributed within the polymer matrix, so that the devices are polarization independent and exhibit a fast response time. Because of the small droplet sizes, …
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