The optical detector characteristics of a silicon solar cell are examined. A general equivalent circuit model is developed and typical parameter values are determined. A comparison is made between the photovoltaic and short circuit operating modes and the short circuit mode is shown to be preferable in terms of linearity, extended frequency response, and temperature stability. A method is developed to determine the noise characteristics of the amplifier-detector system used in the short circuit mode. The silicon solar cell is shown to be an economical alternative to standard photodiodes in low to medium data rate systems.

The wave-kinetic method, a technique developed recently by Tappert and Besieris¹⁻³ or extending conventional ray-tracing methods to incorporate diffractive, refractive, and stochastic effects associated with the propagation of beamed signals, is illustrated in this thesis by considering the propagation of coherent and partially coherent cw Gaussian laser beams in lens-like media (e.g., selfoc fibers, laser induced plasmas, etc.). The main results presented here extend those reported recently in connection with vacuum propagation and deterministic propagation through media characterized by a parabolic profile. Special attention is paid on the irreversible degradation of the focusing ability of a beam due to random imperfections in a lens, with allowance for the presence of a medium having a parabolic profile. / Master of Science

Includes bibliographical references (leaves 151-163). Investigates the behaviour of the intensity noise in a multimode Nd:YAG laser. The collective modes of oscillation are excited by broadband ambient noise. Because the phase of the excitation is unknown, a cross spectral technique to measure the antiphase dynamics directly and form a picture of the intensity noise interference for two to five mode operation is developed. For three mode operation, the contributions of the longitudinal modes to collective modes is measured.

Includes bibliographical references. Electronic publication; full text available in PDF format; abstract in HTML format. Investigates the behaviour of the intensity noise in a multimode Nd:YAG laser. The collective modes of oscillation are excited by broadband ambient noise. Because the phase of the excitation is unknown, a cross spectral technique to measure the antiphase dynamics directly and form a picture of the intensity noise interference for two to five mode operation is developed. For three mode operation, the contributions of the longitudinal modes to collective modes is measured. Electronic reproduction.[Australia] :Australian Digital Theses Program,2001. ix, 163 leaves : ill., charts ; 30 cm.

In this thesis, my main focus was to establish a novel composite-cavity fibre laser (CCFL) and to apply it in sensing, particularly in the hydrophone application. The CCFL that I have proposed is formed by writing three wavelength matched fibre Bragg gratings directly into a continuous length of doped fibre. I have also examined the relative advantages and disadvantages of interferometric and intensity-based hydrophone systems, and have established a hydrophone system that can be switched between the two modes of operation, by making use of digital signal processing. I have established a theoretical model to study the lasing and spectral characteristics of the CCFL. My analysis showed that whilst the CCFL have significantly different phase and threshold conditions from the common semiconductor diode lasers with external cavity, the CCFL also have mode-limiting properties that are often sought after. Through simulations, I was able to identify that a non-uniform straining scheme, that is, when one of the sub-cavities of the CCFL is restrained from strain, can improve the sensitivity with respect to existing single cavity fibre lasers, in both the frequency and intensity domains. My simulations also showed that the sensitivity of such a straining scheme can be optimised by tuning the reflectivity of the gratings, sub-cavity lengths, doping concentration and pump power. I have fabricated multiple CCFLs using the in-house grating writing facilities, and have experimentally assessed their power and spectral related lasing characteristics. Whilst having a significantly longer total cavity length compared to typical fibre lasers, the CCFLs demonstrated stable single longitudinal mode operation and narrow linewidth in the order for a few tens of kHz. Asymmetric output power and frequency as a result of unequal sub-cavity lengths were also examined. Finally, I conducted sensing experiments by applying the CCFLs in strain monitoring and intensity-based hydrophone. My results showed that the non-uniform straining scheme had significantly improved the intensity response of the CCFL, and that the acoustic pressure and frequency can be determined by directly sampling and applying Fourier transform to the output intensity of the fibre laser.

Bibliography: leaves 154-156. / 156 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis describes the construction of a low-power end pumped Nd:YAG laser and the subsequent theoretical and experimental investigation of the antiphase dynamics exhibited by the laser. The end pumped laser was modelled by extending the classical model of Tang Statz deMars to non-uniform pump along the active medium. The anomalous threshold behaviour of the laser, where modes with lower gain can supass modes with higher gain as the pump power increases, was accounted for. The antiphase dynamics were explored by modulating the pump power and measuring the transfer functions from this input to various outputs. The laser's response to various sources of noise was also studied. / Thesis (Ph.D.)--University of Adelaide, School of Chemistry and Physics, Discipline of Physics and Mathematical Physics, 2003?

Also issued as a Ph.D. thesis in the Dept. of Electrical Engineering, 1971. / Bibliography: p. 93-95.

No description available.

Title from PDF of title page (University of Missouri--Columbia, viewed on March 10, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. Gregory E. Triplett Jr. Includes bibliographical references.

Thesis (Ph. D.)--School of Electrical and Computer Engineering, Georgia Institute of Technology, 2004. Directed by Stephen E. Ralph. / Vita. Includes bibliographical references (leaves 281-296).