Thesis (M. Phil.)--University of Hong Kong, 2009. / Includes bibliographical references. Also available in print.

Thesis (doctoral)--University of Oulu, 2005. / Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.S.)--University of Wisconsin--Madison, 1970. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

No description available.

One of the problems associated with the automatic image processing of satellite photographs such as weather maps is the need for image registration; that is, the fitting of a map that has some translational and rotational bias to a known data base. This paper investigates a least square method of image registration using an image that has been converted into a boundary map with a pixel representation 1 for land, -1 for water and zero for cloud pixels. A sampled correlation array is constructed by shifting the weather map to locations on a given grid, centered around a sampled correlation peak, and performing an accumulation of the pixel-by-pixel comparisons between the weather map and its data base over the whole map or a smaller search window. A least square approximation 0 f the translational and rotational bias is performed using the data from this sampled correlation array, fitted against the shape of an elliptical cone.

No description available.

The requirement for a fast automated correlation algorithm for registration of satellite images is discussed. An overview of current registration techniques is presented indicating a correlator, matching binary maps compressed from the original imagery, may provide the required throughput when implemented with a dedicated hardware/processor. An actual registration problem utilizing GOES digitally processed imagery is chosen and defined. The realization of a fast correlator, matching image input data with sampled data base reference image data in real time is considered.

Since the discovery of optical bistability a considerable amount of research activity has been aimed toward the realization of general-purpose all-optical computers. The basic premise for most of this work is the widely held notion that a reliable optical switch can be fabricated from a piece of optically bistable material. To date only a very small number of published articles have addressed the subject of the engineering issues (that is, the optimization and tolerancing) of these optical switches. This dissertation is a systematic treatment of these issues. From the starting point of Maxwell's equations a simple model of optically bistable Fabry-Perot etalons is outlined, in which the material is assumed to be a pure Kerr medium having linear absorption. This model allows for a relatively straightforward optical switch optimization procedure. The procedure is applicable for optimizing any number of switch parameters. The emphasis in this dissertation is on the optimization of the contrast of the switch's output signals, with the other parameters (switching energy, tolerance sensitivity) assuming a secondary yet critical role. Following the optimization of the optical switch is a tolerance analysis which addresses the manufacturability and noise immunity of the optimized switch. In the first part of this analysis equations describing the propagation of errors through a large scale system of like devices are derived from the truth tables of the switches themselves. From these equations worst case tolerances are established on the optical switch's transfer function parameters. In the second part of the tolerance analysis the bistability model is used to arrive at tolerances on the physical parameters of the switch. These tolerances are what determine the manufacturability of the optical switches. The major conclusion of the dissertation is that, within the range of validity of the model and the other simplifying assumptions, optically bistable Fabry-Perot etalons cannot be used reliably as logic gates in large-scale computing systems.

Optical signal processing plays a key role in a high capacity all-optical communication network. Rapid advances in the processing technology offers new solutions to enhance fiber communications. This thesis focuses on the development of new components and techniques for optical signal processing. / The application of optical nonlinearities in fibers and in semiconductor devices is of great importance in different fields of research. In this thesis, we report our findings in the development of new techniques for photonic signal processing. Two different approaches for extinction ratio enhancement of an amplitude-shift keying (ASK) signal have been demonstrated using self-phase modulation in a highly nonlinear bismuth oxide fiber. The differential phase-shift keying (DPSK) modulation format is also receiving much attention owing to its improved receiver sensitivity and its higher tolerance to signal degradation by undesired fiber nonlinearities. We demonstrated all-optical processing of DPSK signals using different nonlinear phenomena in a semiconductor optical amplifiers, a dispersion-flattened highly nonlinear photonic crystal fiber, and a highly nonlinear bismuth oxide fiber. Various application areas including extinction ratio enhancement, amplitude noise reduction, phase noise reduction, wavelength conversion and wavelength multicasting have been realized using four-wave mixing, self-phase modulation, and cross-phase modulation in the optical elements. (Abstract shortened by UMI.) / The birefringent comb filter is an important element in the processing of microwave and optical signals. To increase the flexibility in its operation, it is desirable for the filter to be tunable in both the spectral position and the spacing of the comb. By incorporating an electro-optic phase modulator to control the overall birefringence, the output comb can be rapidly modulated in the spectral domain. We also introduced a new architecture of a dual-pass Lyot filter that offers the highest tunability of the comb spacing at a given number of birefringent fiber elements. Selectivity of the spacing is based on different alignments between the fiber axes in our cascadable scheme. We applied the birefringent comb filter to multi-wavelength laser source generation using either a semiconductor or a fiber-based gain element. By electrical tuning of the birefringence inside a semiconductor optical amplifier ring laser, a waveband switchable multi-wavelength source has been obtained. In an erbium-doped fiber (EDF) laser, multi-wavelength lasing is inhibited at room temperature owing to the homogeneously broadened gain medium. To address this problem, two different types of fiber nonlinearities, stimulated Brillouin scattering and four-wave mixing, are incorporated separately to the EDF laser to provide self-stabilization of the multi-wavelength oscillation. In addition to multi-wavelength source generation, we further applied the birefringent comb filter to multiply the repetition rate of a high-speed pulsed source using the spectral elimination approach. Repetition rate multiplication from 10 to 40 GHz has been simultaneously achieved for four ITU-grid laser sources around 1550 nm, resulting in an aggregate pulse rate of 160 GHz. The phase coherence of the output pulses is also preserved. / Fok, Mei Po Mable. / "August 2007." / Adviser: Chester Shu. / Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 1198. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

Optical time-division-multiplexing is another promising solution for high-speed signal generation. Using the in-fiber PCF-MZI, we have also performed OTDM signal generation at different bit rates. The setup offers comparable performance to commercial multiplexers. We generated 160-Gb/s and 320-Gb/s OTDM signals based on PCF-MZIs. / Orthogonol frequency division multiplexing (OFDM) has attracted quite a lot of interests due to its incomparable advantages in high spectral efficiency optical communication, which significantly enlarges the optical transmission capacity. Optical demultiplexing (DEMUX) of OFDM signals requires FFT processing, which can be efficiently achieved by using cascaded delay interferometers. We theoretically and experimentally studied the transmission properties of cascaded and multi-section Sagnac interferometers and demonstrated their application for the optical OFDM DEMUX. 4-channel OFDM DEMUX is experimentally demonstrated with open eye obtained. / Our study on optical processing of high speed OTDM signals continues with fiber-based techniques using third order nonlinear effects. Based on HNLF, we can construct active fiber interferometer, namely here as nonlinear optical loop mirrors (NOLM). We investigate dispersion asymmetric nonlinear optical loop mirror (DA-NOLM) based on cross phase modulation for simultaneous two-channel demultiplexing (DEMUX) usmg only a single baseband control pulse. Reconfigurable DEMUX has been achieved for 40-Gb/s OTDM signals. The DEMUX are also switchable between two-channel and single-channel operations. Utilizing the tunable delay, DA-NOLM has also been applied to signal processing including pulse format conversions, and repetition rate multiplication. / Photonic crystal fiber based Mach-Zehnder interferometer (PCF-MZI) is constructed by a single line PCF, which is an in-line, all-fiber and coupler free device. As a delay interferometer (DI), PCF-MZI offers enhanced thermal stability in its operation. To date, applications of the in-fiber PCF-MZI are mainly focused on optical sensing instead of communications, which is a major objective in this thesis work. We have fabricated PCF-MZIs with different PCF lengths to introduce desirable delays for optical signal processmg, including differential phase shift keying (DPSK) demodulation, pulse format conversion, repetition rate multiplication and high speed optical time-division-multiplexing (OTDM) signal generation. / The continuously growing Internet traffic has resulted in a huge amount of data flow in the optical networks, particularly along with the recent developments of 3G/4G service, cloud computing, and Internet of things. High-data-rate optical transmission and interconnection are highly desirable in the near future, for next generation communication networks. Accompanied with the traffic growth is the requirement for faster signal processing technology. In this regard, all-optical processing plays a key role in eliminating optical-electrical-optical conversion, thus offering unmatched operation speed with reduced complexity and power consumption. This thesis focuses on high speed all-optical signal processing technologies based on innovative fiber-based interferometers, including Mach-Zehnder and loop mirror interferometers constructed by photonic crystal fiber (PCF), birefringent fiber and highly nonlinear fiber (HNLF). / We also investigated signal processing using nonlinear devices beyond those fiber interferometers. FWM is utilized for chirp magnification which was successfully applied to optical comb generation for obtaining optical OFDM signals. Optical comb generation with extinction ratio enhancement and flatness improvement is demonstrated utilizing a stimulated Brillouin scattering (SBS) based optical loop mirror. Clock recovery of OTDM-OOK signals has been successfully demonstrated over a wide range of bit rates using the SBS loop mirror. / With dispersion management inside the loop mirror interferometer, we have further proposed and demonstrated a modified DA-NOLM. The new device introduces a larger asymmetry in the propagation of the two interfering branches while maintaining a zero total dispersion in each of them. Consequently, pulse broadening is reduced and higher bit rate operation is supported. With the device, we have successfully achieved error-free two-channel DEMUX for 80-Gb/s OTDM signals. / Du, Jiangbing. / Adviser: Chester Shu. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.