Reproduction de : Thèse de doctorat : Signal, image, acoustique et optimisation : Toulouse, INPT : 2008. / Texte en anglais. Titre provenant de l'écran-titre. Bibliogr. 76 réf.

Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 203-208).

Thesis (Ph.D.)--University of Central Florida, 2008. / Adviser: Peter J. Delfyett, Jr. Includes bibliographical references (p. 123-130).

Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, December 2009. / Thesis Advisor(s): Jenn, David C. Second Reader: Pace, Phillip E. "December 2009." Description based on title screen as viewed on January 28, 2010. Author(s) subject terms: Direct conversion, homodyne, IQ mismatch, DC offsets, IQ circle, phase error, modulator, demodulator calibration, LabVIEW, Directional Finding (DF), digital beamforming, Robust Symmetrical Number System (RSNS). Includes bibliographical references (p. 73-75). Also available in print.

Thesis (Ph. D.)--Brigham Young University. Dept. of Electrical and Computer Engineering, 2004. / Includes bibliographical references (p. 169-181).

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains v, 118, [64] p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 114-118).

Multimode fibers (MMF) are generally used in short and medium haul optical networks owing to the availability of low cost devices and inexpensive packaging solutions. However, the performance of conventional multimode fibers is limited primarily by the presence of high modal dispersion owing to large core diameters. While electronic dispersion compensation methods improve the bandwidth-distance product of MMFs, they do not utilize the fundamental diversity present in the different modes of the multimode fiber. This thesis draws from developments in wireless communication theory and signal processing to motivate the use of multiple-input multiple-output (MIMO) and signal processing techniques in MMF links. MIMO techniques that utilize the diversity of modes present in the fiber increase data rates and link reliability. Theoretical models for propagation effects in MMF systems are used to analyze and design the geometry of laser and detector arrays for MIMO-MMF links, and study how the design of these arrays impacts link performance. These models are also used to develop and evaluate low-complexity algorithms that efficiently utilize dense detector arrays, with "greedy subset selection" based on submodular optimization. Experimental evaluation of 1 × 1, 2 × 2, 3 × 3 and 4 × 4 MIMO systems have been conducted over various MMF media, including 100 m - 3 km silica MMF with externally modulated distributed feedback lasers and directly modulated vertical cavity surface emitting lasers (VCSELs), as well as with Fabry Perot lasers over 10 m - 100 m plastic MMF. The use of off-the-shelf components as well as the role of axial offset coupling in enhancing modal diversity has been experimentally quantified. The experimental techniques discussed in this thesis have enabled an increase of over 25× in the bandwidth-distance product of the MMF link, when compared to currently deployed MMF systems, such as 10GBASE-SR. / text

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Semiconductor nanowire field-effect transistors (NWFET) have been recognized as a possible alternative to silicon-based CMOS technology as traditional scaling limits are neared. The core-shell nanowire structure, in particular, also allows for the enhancement of carrier mobility through radial band engineering. In this thesis, we have evaluated the possibility of electron confinement in strained Si-Si1-xGex core-shell nanowire heterostructures. Cylindrical strain distribution was calculated analytically for structures of various dimensions and shell compositions. The strain-induced conduction band edge shift of each region was found using k•p theory coupled with a coordinate system shift to account for strain. A positive conduction band offset of up to 200 meV was found for a Si-Si0.2Ge0.8 structure. We have also designed and characterized a modulation doping scheme for p-type, Ge-SiGe core-shell NWFETs. Finite element simulations of hole density versus radial position were done for different combinations of dopant position and concentration. Three modulation doped nanowire samples, each with a different boron doping density in the shell, were grown using a combined vapor-liquid-solid and chemical vapor deposition process. Low temperature current-voltage measurements of bottom- and top-gate samples indicate that hole mobility is limited by the proximity of charged impurities. / text

published_or_final_version / Electrical Engineering / Master / Master of Philosophy