Optical interconnects have attracted great interest as data rates continue to increase. When compared with their electrical counterparts, optical interconnects have significant advantages in terms of crosstalk, bandwidth, distance, and latency. Many applications stand to benefit from low-cost, high-speed integrated optical transceivers with single-channel gigabit data rates. As in the case of RF wireless designs, using CMOS technology is of special interest due to the potential of lower cost and higher integration. The analog frontend is a key component in optical receivers due to its importance in bridging the optical and electrical signal domains. In this work, we present a 10 Gb/s optical receiver frontend designed and fabricated in ST’s 90 nm CMOS technology. The receiver contains a transimpedance (pre)amplifier (TIA), and limiting amplifier (LA), and an output buffer (OB). The TIA demonstrates a transimpedance gain of 61.9 dB Ohm and a bandwidth of 7.4 GHz, trading off noise and ISI considerations. The single-ended design utilizes 1.5 mW of power from a 1.0 V supply. The LA demonstrates a voltage gain of 21 dB and a bandwidth extended to 10 GHz using inductive peaking. The differential design utilizes 3.9 mW of power from a 1.0 V supply. Finally, the output buffer is capable of driving large output voltage swings to 50 Ohm on-chip terminations. In order to test the receiver, a PCB and testing strategy is co-designed with the chip. Details concerning the various design decisions, tradeoffs, are discussed in this thesis. Experimental results of a fabricated device are presented under ideal and practical system levels, with data rates up to 8.5 Gb/s. / Les interconnexions optiques ont attiré grand intérêt pendant que les flux d’information continuent à augmenter. En comparaison avec leurs contre-parties électriques, les interconnexions optiques ont des avantages significatifs en termes d’interférence, largeur de bande, distance, et latence. En raison de ces avantages, beaucoup d’applications se tiennent pour des bénéfices des récepteurs optiques intégrés peu coûteux et à grande vitesse.Le devant analogue dans les récepteurs optiques est une composante clé, son importance en jetant un pont sur les domaines de signal optique et électrique. Dans ce travail, nous présentons un récepteur optique 10 Gb/s conçu et fabriqué en technologie CMOS à 90 nanomètre. Le récepteur contient un (pré)amplificateur de transimpedance (TIA), un l’amplificateur limiter (LA), et un amortisseur de rendement (OB). Le TIA démontre un gain de transimpedance de 61.9 dB Ohm et d’une largeur de bande de 7.4 gigahertz, en balançant les considérations de bruit et de l’inteférance des symboles. La conception utilise 1.5 mW de puissance à un tension de 1.0 V. La LA démontre un gain de 21 dB et une largeur de bande prolongée à 10 gigahertz utilisant une pointe inductif. La conception différentielle utilise 3.9 mW de puissance à un tension de 1.0 V. En conclusion, l’amortisseur de rendement est capable de conduire de grandes oscillations de tension de rendement aux arrêts de 50 Ohm. Afin d’examiner le récepteur, une affiche PCB et une stratégie d’essai conçue avec le circuit est présenté. Des détails au sujet des diverses décisions de conception et défi sont discutés dans cette thèse. Des résultats expérimentaux d’un circuit fabriqué sont présentés sous les niveaux système idéaux et pratiques, avec des vitesses jusqu’à 8.5 Gb/s.

The complete design of many electromagnetic devices requires the solution of a coupled problem. Typically, the coupling is in the form of magnetic/thermal, magnetic/structural, magnetic/electronic, or possibly a combination of several disciplines. Computer based tools exist for many of these engineering specializations but they are usually "stand-alone" and each requires an experienced designer to use it effectively. This requirement for an expert user places a major constraint on the design cycle, and a lack of communication between the various experts can result in major design errors. / This thesis proposes a software architecture that is capable of providing loose coupling between currently available design tools and of absorbing new tools in the future. The structure provides an integration environment for a suite of design programs. The environment automatically allows the iterative solution of coupled problems by loosely coupling individual tools through a comprehensive database and organizing their execution via a rule-based control program. In order to effectively integrate a diverse set of tools and to define the kind of coupling between the various analyses, it is necessary that the input and output requirements of each tool be carefully defined. The BlackBoard for Computational Analysis and Design (BBCAD) is a hybrid knowledge-based system which uses the blackboard architecture, and generates a systematic method of integrating the "stand-alone" design tools, together with an automatic method of ensuring that, if a change is made to the design, all the relevant design tools are re-run.

An adaptive finite element method is developed to solve two dimensional unbounded electromagnetic radiation and scattering problems. / Though there has been considerable research in adaption in electromagnetics, to date there have been few attempts to deal with adaptively reducing the error introduced by the boundary that artificially truncates the unbounded domain in a finite element analysis. The technique proposed here adapts on this boundary error, as well as on the usual finite element discretization error. It combines three techniques: (i) p-adaptive hierarchial triangular finite elements, (ii) wave-envelope elements and (iii) absorbing boundary conditions. / Hierarchial finite elements allow the polynomial orders of the elements to be used to control the distribution of degrees of freedom, and therefore they make p-adaption possible, i.e. adaption by varying the element orders. This is more efficient than h-adaption which requires an actual re-meshing of the finite elements. / The wave-envelope method uses a change of dependent variable to remove the wave-like qualities of the solution and thereby permits the use of very large elements, i.e. elements much larger than a wavelength, in the external domain. / An absorbing boundary condition is a boundary operator which approximately absorbs all the radiation incident on the boundary from within. / In the new method, the scattering or radiating object itself, and its immediate surroundings, are meshed with hierarchial finite elements. Outside that, a thick layer of free space is meshed with hierarchial wave-envelope elements. The layer is thick enough that when an absorbing boundary condition is imposed on its outer surface, there is very small reflection from it. Such a thick layer can be meshed with relatively few wave-envelope elements. The boundary error seen by the finite element region is then a function of how well the wave-envelope region is discretized. During the p-adaption, increasing the order of the wave-envelope elements increases their ability to model the field accurately and therefore reduces the boundary error. Moreover, this reduction in boundary error is selective: in directions of strong radiation, the error reduction is greater. / The new method is validated by comparison with exact solutions for a number of radiation and scattering problems over a range of frequencies.

There has been an ongoing effort to achieve very high quality speech coding at medium transmission bit rates. Consequently, the TIA has chosen the Vector SUM Linear Predictive (VSELP) implementation of an 8 kb/s coder to be the standard for North-American cellular digital telephony. However, it was only recently that, in view of the increased research focus on developing toll-quality speech coding at such bit rates, the CCITT has imposed a set of specifications for standardizing low-delay coders operating at 8 kb/s. The Low-Delay Code Excited Linear Predictive (LD-CELP) suggested by Chen is presently the only potential candidate for CCITT standardization, achieving a one-way coding delay of 10 ms. However, just like the VSELP coding algorithm, the 8 kb/s LD-CELP version does not quite yield toll-quality reconstructed speech. The purpose of the work in this thesis is to establish the minimum requirements for a coding structure capable of generating toll-quality coded speech at 8 kb/s. The purpose of this thesis is to show that, by slightly relaxing the coding delay constraint, perceptual enhancement techniques yield toll quality coding after redesigning and fine-tuning the optimization and quantization procedures of a CELP coder.

As digital systems become widespread, the importance of error control in these systems increases. Further, since most channels cannot be realistically modelled by a simple Binary Symmetric Channel, it is required to reliably estimate the performance of error control schemes on real channels. This thesis considers the analysis and simulation of a Generalised Hybrid ARQ Type II (GH-ARQ II) error control scheme on a channel modelled by the Gilbert-Elliott model. The analysis is easily extended to higher order systems and channels modelled by first-order Markov chains. The results indicate that the performance of the GH-ARQ II scheme improves as the errors in the channel become burstier in nature and that this scheme is well suited to channels with relatively slowly varying error statistics. Further, it is found that the roundtrip delay of the selective repeat retransmission strategy may affect the performance of this error control scheme on burst-noise channels.

The Beam Propagation Method (BPM) together with an accurate Effective Index model is used as a Computer Aided Design (CAD) tool for the analysis, design and optimization of integrated optical devices. The performance of both active and passive 3-branch Ti:LiNbO$ sb3$ waveguide devices as a function of various design parameters is investigated. Then, the device design required to match a specified performance is deduced, and the theoretical performance predictions are verified experimentally through device fabrication and measurements. / In particular, a 3-branch passive power divider, a linear mode confinement modulator, and an active 3-branch switch were studied through their design and implementation. The theoretically predicted performance parameters were found to agree well with the measured values.

This thesis studies low-rate wideband analysis-by-synthesis speech coders. The wideband speech signals have a bandwidth of up to 8 kHz and are sampled at 16 kHz, while the target operating bit rate is 16 kbits/sec. Applications for such a coder range from high-quality voice-mail services to teleconferencing. In order to achieve a low operating rate, the coding places more emphasis on the lower frequencies (0 to 4 kHz), while the higher frequencies (4 to 8 kHz) are coded less precisely but with little perceived degradation. / The study consists of three stages. First, aspects of wideband spectral envelope modeling using Line Spectral Frequencies (LSF's) are studied. Then, the underlying coder structure is derived from a basic Residual Excited Linear Predictive coder (RELP). This structure is enhanced by the addition of a pitch prediction stage, and by the development of full-band and split-band pitch parameter optimization procedures. These procedures are then applied to an Code Excited Linear Prediction (CELP) model. Finally, the performance of full-band and split-band CELP structures are compared.

Many specialized processor boards have been developed to reduce the computation time of image processing algorithms. However, floating point processing required by complex algorithms has to be performed on general purpose computers since no specialized processor operates in floating point arithmetic. This thesis presents the VLSI design of a systolic cell to be used in a double precision floating point convolution processor. The CMOS technology was used to implement the design of the custom VLSI chip. Data flows in the systolic array in such a way that it is not only used when input but resued by every systolic cell in a pipelined fashion. This parallel processing approach reduces the computation time required by current workstations by three orders of magnitude while providing the same precision.

In this thesis we consider a number of issues in developing techniques and algorithms to automate the visual tracking of deformable objects in the plane. We have applied these techniques in cell locomotion and tracking studies. First, we consider the segmentation of a noisy intensity image and the tracking of a nonrigid object. Second, we consider the shape analysis of an amorphous object. In evaluating these problems, we explore a new technique based on an active contour model commonly called a "snake". We present a detailed analysis of the snake model, emphasizing its limitations and shortcomings, and propose various improvements to the original description of the model. Then, we study the two complementary types of shape descriptors: boundary- and region-based. We propose to combine these within the context of the grassfire transform. Two new algorithms are described. First, we present a contour segmentation technique using mathematical morphology on the curvature function. Accurate localization for different scales of curvature features is achieved. Second, the snake model is used to simulate the grassfire transform using the previously extracted contour features.

Planar optical waveguides made by purely thermal and electric field-assisted $K sp{+} - Na sp+$ ion-exchange in soda-lime glass substrates are investigated. / Buried waveguides fabricated by a purely thermal backdiffusion process have been demonstrated, for the first time, on soda-lime glass. The diffusion properties, such as the potassium-ion concentration, are determined experimentally using a scanning electron microscope (SEM) and electron probe microanalyzer (EPMA). These properties are then compared to the numerical modeling of the non-linear ion-exchange process and correlated to the waveguide propagation characteristics, such as the refractive index profile. The single-mode dispersion curves are computed by a simple Runga-Kutta procedure and compared to the measured effective mode indices. / An experimental characterization of surface waveguides made by an electric field-assisted process with respect to a wide range of fabrication conditions are studied, including measurements of polarization-dependent propagation characteristics. Parallel to this, the diffusion properties are numerically simulated and correlated to the SEM data, providing an accurate description of the refractive index profile.