Digital Commons Network^™

Additive Lithography Fabrication And Integration Of Micro Optics, Mahesh Pitchumani

Electronic Theses and Dissertations

Optical elements are the fundamental components in photonic systems and are used to transform an input optical beam into a desired beam profile or to couple the input beam into waveguides, fibers, or other optical systems or devices. Macroscopic optical elements are easily fabricated using grinding and polishing techniques, but few methods exist for inexpensive fabrication of micro optical elements. In this work we present an innovative technique termed Additive Lithography that makes use of binary masks and controlled partial exposures to sculpt photoresist into the desired optical surface relief profile. We explore various masking schemes for fabricating a variety …

Up-Conversion In Rare-Earth Doped Micro-Particles Applied To New Emissive 2d Dislays, Anne Milliez

Electronic Theses and Dissertations

Up-conversion (UC) in rare-earth co-doped fluorides to convert diode laser light in the near infrared to red, green and blue visible light is applied to make possible high performance emissive displays. The infrared-to-visible UC in the materials we study is a sequential form of non-linear two photon absorption in which a strong absorbing constituent absorbs two low energy photons and transfers this energy to another constituent which emits visible light. Some of the UC emitters' most appealing characteristics for displays are: a wide color gamut with very saturated colors, very high brightness operation without damage to the emitters, long lifetimes …

Synchronization In Advanced Optical Communications, Inwoong Kim

Electronic Theses and Dissertations

The objective of this dissertation is to generate high power ultrashort optical pulses from an all-semiconductor mode-locked laser system. The limitations of semiconductor optical amplifier in high energy, ultrashort pulse amplification are reviewed. A method to overcome the fundamental limit of small stored energy inside semiconductor optical amplifier called "eXtreme Chirped Pulse Amplification (X-CPA)" is proposed and studied theoretically and experimentally. The key benefits of the concept of X-CPA are addressed. Based on theoretical and experimental study, an all-semiconductor mode-locked X-CPA system consisting of a mode-locked master oscillator, an optical pulse pre-stretcher, a semiconductor optical amplifier (SOA) pulse picker, an …

Direct Nonlinear Optics Measurements Of Raman Gain In Bulk Glasses And Estimates Of Fiber Performance, Robert Stegeman

Electronic Theses and Dissertations

The need for more bandwidth in communications has stimulated the search for new fiberizable materials with properties superior to fused silica which is the current state-of-the-art. One of the key properties is Raman gain by which a pump beam amplifies a signal beam of longer wavelength. An apparatus capable of directly measuring the spectral dependence and absolute magnitude of the material Raman gain coefficient using nonlinear optics techniques has been built. Using radiation from a 1064 nm Nd:YAG laser as the pump and from a tunable Optical Parametric Generator and Amplifier as the signal, the Raman gain spectrum was measured …

Integrated Inp Photonic Switches, Daniel May-Arrioja

Electronic Theses and Dissertations

Photonic switches are becoming key components in advanced optical networks because of the large variety of applications that they can perform. One of the key advantages of photonic switches is that they redirect or convert light without having to make any optical to electronic conversions and vice versa, thus allowing networking functions to be lowered into the optical layer. InP-based switches are particularly attractive because of their small size, low electrical power consumption, and compatibility with integration of laser sources, photo-detectors, and electronic components. In this dissertation the development of integrated InP photonic switches using an area-selective zinc diffusion process …

Effect Of Germanium Doping On Erbium Sensitization In The Erbium Doped Silicon Rich Silica Material System, Forrest Ruhge

Electronic Theses and Dissertations

The continued size reduction in electronic integrated circuits has lead to a demand for on-chip high-bandwidth and low loss communication channels. Optical interconnects are considered an essential addition to the silicon electronics platform. A major challenge in the field of integrated Si photonics is the development of cost effective silicon compatible light sources. This thesis investigates the sensitization of group IV doped silica films emitting at 1.535μm for applications as silicon compatible light sources. Thin erbium-doped silica films containing excess silicon and germanium were deposited using a multi-gun sputter system. The composition of the deposited materials was verified by Rutherford …

External Cavity Multiwavelength Semiconductor Mode-Locked Laser Gain Dynamics, Luis Archundia-Berra

Electronic Theses and Dissertations

External cavity semiconductor mode-locked lasers can produce pulses of a few picoseconds. The pulses from these lasers are inherently chirped with a predominant linear chirp component that can be compensated resulting in sub-picosecond pulses. External cavity semiconductor mode-locked lasers can be configured as multiwavelength pulse sources and are good candidates for time and wavelength division multiplexing applications. The gain medium in external cavity semiconductor mode-locked lasers is a semiconductor optical amplifier (SOA), and passive and hybrid mode-locked operation are achieved by the introduction of a saturable absorber (SA) in the laser cavity. Pump-probe techniques were used to measure the intracavity …

High Birefringence And Low Viscosity Liquid Crystals, Chien-Hui Wen

Electronic Theses and Dissertations

In this dissertation, liquid crystal (LC) materials and devices are investigated in order to meet the challenges for photonics and displays applications. We have studied three kinds of liquid crystal materials: positive dielectric anisotropic LCs, negative dielectric anisotropic LCs, and dual- frequency LCs. For the positive dielectric anisotropic LCs, we have developed some high birefringence isothiocyanato tolane LC compounds with birefringence ~0.4, and super high birefringence isothiocyanato biphenyl-bistolane LC compounds with birefringence as high as ~0.7. Moreover, we have studied the photostability of several high birefringence LC compounds, mixtures, and LC alignment layers in order to determine the failure mechanism …

Next Generation Heterogenous Telemetry Modules, Pierce Brady

Theses

Remote monitoring is used in many applications within the scientific, industrial and commercial communities. These applications can range from the simple monitoring of wind farm generators to the complex behavioural monitoring of a local fox habitat to the simple but extremely urgent monitoring of water depth for a flood prone river. Each application of remote monitoring requires different aspects of the remote monitoring device, but typically, not all these applications can be implemented, as the technologies required for their construction are extremely large, expensive, energy inefficient, slow and do not meet the constraints for the given application.

However with the …

Digital Channelized Wide Band Receiver Implemented With A Systolic Array Of Multi-Rate Fir Filters, David M. Rodney

Browse all Theses and Dissertations

This thesis proposes the use of a Systolic Array of Multi-Rate FIR Filters to improve performance by eliminating the requirement of the FFT and De-Multiplexer associated with the conventional receiver while achieving the same functionality. The FFT is a major bottle neck for improving system performance for the conventional DCWBR because many complex multiplications and additions are required. The proposed new architecture is designed and evaluated in MATLAB to illustrate its viability. Two approaches for improved channel arbitration are accessed in MATLAB, namely, channel bin’s rms comparison and parallelism of the Systolic Array Multi-Rate FIR Filters. The FIR filters (high-pass …

Fpga Frequency Domain Based Gps Coarse Acquisition Processor Using Fft, Cyprian D. Sajabi

Browse all Theses and Dissertations

The Global Positioning System or GPS is a satellite based technology that has gained widespread use worldwide in civilian and military applications. Direct Sequence Spread spectrum (DSSS) is the method whereby the data transmitted by the satellite and received by user is kept secure, low power and relatively noise-immune. The first step required in the GPS operation is to perform a lock on the incoming signal, both with respect to time synchronization and frequency resolution. Because of the need for reduced time to lock and also reduced hardware, algorithms based in the frequency domain have been developed. These algorithms take …

Implementation Of A Multi-Layered Fuzzy Controller On An Fpga, Ajit Paal Singh Khatra

Browse all Theses and Dissertations

The uses of Autonomous Mobile robots range from the teleoperated Sojourner on the Mars Pathfinder mission to cleaning robots in the Paris Metro. They have overtaken tasks which are too difficult or dangerous to perform or require the repetition of the same procedure over and over again and can become dull for a human to perform. The objective of this thesis is to develop and implement a multilayered fuzzy controller on an FPGA for the navigational control of an autonomous mobile robot (AMR). The navigational algorithm assists the robot in navigating through complex environments of passages and hallways. The FPGA …

Direct Digital Frequency Synthesizer Implementation Using A High Speed Rom Alternative In Ibm 0.13u Technology, Matthew R. Gerald

Browse all Theses and Dissertations

The direct digital synthesizer is a method of signal generation with many benefits. DDS designs are able to switch frequencies very quickly and also tune precisely to many different frequencies with the use of a constant operating frequency. There is a need for a low power, high speed DDS in the form an ASIC design. One major bottleneck in common DDS systems is the slow access time of a ROM. There is also a need for a high speed ROM alternative. This thesis delivers a high speed ASIC Direct Digital Synthesizer which operates at a 1 GHz operating frequency. This …

Chirp Signaling Offers Modulation Scheme For Underwater Communications, Edit J. Kaminsky

Electrical Engineering Faculty Publications

Information contained in the slope of chirp signals can be employed for digital underwater acoustic communications across a broad range of applications.

A Simple Improvement To The Viterbi And Viterbi Monomial-Based Phase Estimators, Kenneth V. Cartwright, Edit J. Kaminsky

Electrical Engineering Faculty Publications

It is well known that the Viterbi and Viterbi Monomial- Based Phase Estimator, which includes the Mth Power Estimator, performs poorly for cross QAM signals. However, it is shown here that by allowing the power of the monomial to be negative, much improved performance can be realized at medium to high signalto- noise ratios (SNR). Monte Carlo simulations are used to demonstrate the efficacy of this novel simple extension, for 32- and 128-QAM systems. In principle, this extension can also be applied to other constellations, e.g., (4,12)-PSK.

Performance And Spectral Analysis Of Q2psk And Ce Q2psk Systems In Ideal Bandlimited Channels, Milton I. Quinteros, Edit J. Kaminsky, Kenneth V. Cartwright

Electrical Engineering Faculty Publications

The authors present theoretical performance analysis and simulation results for Quadrature-Quadrature Phase Shift Keying (Q2PSK), Constant Envelope (CE) Q2PSK, and trelliscoded 16D CEQ2PSK in ideal bandlimited channels of various bandwidths. The performance of receivers with and without channel estimation is reported. Spectral analysis is presented for each system, in addition to MSK and expanded uncoded 16D CEQ2PSK. We show that the effects of bandlimiting are most severe for Q2PSK. Knowledge of the channel information aids 4D CEQ2PSK the least. Only 6.8 dB of SNR is needed for the TCM system for a bit error rate of 10−5 for the narrowest …

Miniature Circularly Polarized Rectenna With Reduced Out-Of-Band Harmonics, Mohammod Ali, Guangli Yang, Roger A. Dougal

Faculty Publications

Wireless embedded sensors are becoming increasingly important for many safety critical applications. Sensor batteries or capacitors must be charged as needed in order to achieve high data rate communications. A miniature circularly polarized rectenna operating at 5.5 GHz is introduced which, with the help of an integrated band-reject filter, reduces out-of-band harmonic emission significantly. The rectenna has a conversion efficiency of 74% with more than 50 dB out-of-band harmonic suppression at 11 GHz.

Thermo-Mechanical Characterization Of Copper Through-Wafer Interconnects, Peter A. Miranda, Amy J. Moll

Electrical and Computer Engineering Faculty Publications and Presentations

Copper through wafer interconnects (TWIs) have become a viable solution to providing interconnectivity between stacked die. In a world where minimizing chip real estate while increasing functionality is the goal for further miniaturization of electronics, TWIs hold a key role as new packaging schemes become critical for overall higher density. Little is known, however, about the impacts of mismatched coefficients of thermal expansion (CTEs) inherent to the materials used in their construction. CTE differences, if left unresolved, can pose reliability issues during TWI operation. This research focuses on providing insight into the stress levels experienced by TWI materials through finite …

Using Rfid Technology In Collaborative Design Of The Assembly Systems, Stevan Stankovski, Gordana Ostojić, Vukica Jovanović, Branislav Stevanov

Engineering Technology Faculty Publications

Modern production conditions require the application of the concept of distributing production. This approach means coordinative production in a number of small and middle size companies. Multiplex products, consisting of a number of parts, components, and modules are assembled in one function unit in one company, but they may not be manufactured in one place. Huge factory and production complex, which existed in our country, comprised all phases of product lifecycle, from the development of a concept solution to the assembly. Technology of product manufacturing, resource logistics, quality control, product testing and verification of product function characteristics all represented activities …

Design And Optimization Of Nano-Optical Elements By Coupling Fabrication To Optical Behavior, Raymond Rumpf

Electronic Theses and Dissertations

Photonic crystals and nanophotonics have received a great deal of attention over the last decade, largely due to improved numerical modeling and advances in fabrication technologies. To this day, fabrication and optical behavior remain decoupled during the design phase and numerous assumptions are made about "perfect" geometry. As research moves from theory to real devices, predicting device behavior based on realistic geometry becomes critical. In this dissertation, a set of numerical tools was developed to model micro and nano fabrication processes. They were combined with equally capable tools to model optical performance of the simulated structures. Using these tools, it …

Predicting Surface Scatter Using A Linear Systems Formulation Of Non-Paraxial Scalar Diffraction, Andrey Krywonos

Electronic Theses and Dissertations

Scattering effects from rough surfaces are non-paraxial diffraction phenomena resulting from random phase variations in the reflected wavefront. The ability to predict these effects is important in a variety of applications including x-ray and EUV imaging, the design of stray light rejection systems, and reflection modeling for rendering realistic scenes and animations of physical objects in computer graphics. Rayleigh-Rice (small perturbation method) and Beckmann-Kirchoff (Kirchhoff approximation) theories are commonly used to predict surface scatter effects. In addition, Harvey and Shack developed a linear systems formulation of surface scatter phenomena in which the scattering behavior is characterized by a surface transfer …

Efficient Scheduling For Sdmg Cioq Switches, Mei Yang, S. Q. Zheng

Electrical & Computer Engineering Faculty Research

Combined input and output queuing (CIOQ) switches are being considered as high-performance switch architectures due to their ability to achieve 100% throughput and perfectly emulate output queuing (OQ) switch performance with a small speedup factor S. To realize a speedup factor S, a conventional CIOQ switch requires the switching fabric and memories to operate S times faster than the line rate. In this paper, we propose to use a CIOQ switch with space-division multiplexing expansion and grouped input/output ports (SDMG CIOQ switch for short) to realize speedup while only requiring the switching fabric and memories to operate at the line …

Porous Silicon Technology For Integrated Microsystems, Jin Zheng Wallner

Dissertations, Master's Theses and Master's Reports - Open

With the development of micro systems, there is an increasing demand for integrable porous materials. In addition to those conventional applications, such as filtration, wicking, and insulating, many new micro devices, including micro reactors, sensors, actuators, and optical components, can benefit from porous materials. Conventional porous materials, such as ceramics and polymers, however, cannot meet the challenges posed by micro systems, due to their incompatibility with standard micro-fabrication processes. In an effort to produce porous materials that can be used in micro systems, porous silicon (PS) generated by anodization of single crystalline silicon has been investigated.

In this work, the …

A Corpus-Based Concatenative Speech Synthesis System For Turkish, Haşi̇m Sak, Tunga Güngör, Yaşar Safkan

Turkish Journal of Electrical Engineering and Computer Sciences

Speech synthesis is the process of converting written text into machine-generated synthetic speech. Concatenative speech synthesis systems form utterances by concatenating pre-recorded speech units. Corpus-based methods use a large inventory to select the units to be concatenated. In this paper, we design and develop an intelligible and natural sounding corpus-based concatenative speech synthesis system for the Turkish language. The implemented system contains a front-end comprised of text analysis, phonetic analysis, and optional use of transplanted prosody. The unit selection algorithm is based on commonly used Viterbi decoding algorithm of the best-path in the network of the speech units using spectral …

Sturm-Liouville Equation: The Bridge Between Eigenvalue And Green's Function Problems, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

This article is intended as an educational aid and discusses guided wave propagation problems that are modeled via the Sturm-Liouville equation in electromagnetics. The bridge between source-free (eigenvalue) and source-driven (Green's function) problems that are represented by the same Sturm-Liouville equation is emphasized. The presentation focuses on representation of an arbitrary source from the features (eigenfunctions) of the problem geometry and extraction of the eigenvalues of a problem from propagation characteristics (Green's function) on a canonical problem; a homogeneously filled parallel plate waveguide with non-penetrable boundaries

State-Space Synthesis Of Current-Mode First-Order Log-Domain Filters, Ali̇ Kirçay, Uğur Çam

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes current-mode first-order log-domain filters, which are systematically derived using the state-space synthesis procedure. First-order low-pass, high-pass, and all-pass responses are obtained with different circuit types. The filter circuits have very simple structures, since they use only bipolar junction transistors (BJTs) and a grounded capacitor. They can be electronically tuned by changing an external current. The filters have a greater bandwidth due to inherently current-mode and log-domain operation. PSPICE simulations are given to confirm the theoretical analysis.

Electrical And Computer Engineering Education In The 21^{St} Century: Issues, Perspectives And Challenges, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.

Infusing Technical Communication And Teamwork Within The Ece Curriculum, By April Kedrowicz, Sundy Watanabe, Damon Hall, Cynthia Furse

Turkish Journal of Electrical Engineering and Computer Sciences

This paper highlights a unique approach to infusing formal training and practice in oral and written communication and teamwork development in the Department of Electrical and Computer Engineering (ECE) at the University of Utah. Faculty and graduate (Ph.D.) students from the College of Humanities have teamed up with faculty from engineering to develop communication and teamwork instruction that is integrated into the existing engineering curriculum. These skills are used as a vehicle to provide better understanding of engineering concepts and their applications.

Secure Digital Communication Using Chaotic Symbolic Dynamics, Ajeesh P. Kurian, Sadasivan Puthusserypady

Turkish Journal of Electrical Engineering and Computer Sciences

One of the major hurdles in implementing chaotic communication schemes is the synchronization of chaotic systems. For the last two decades, numerous contributions of varying successes have been made by researchers from different disciplines for the synchronization of chaotic systems. Symbolic dynamics based synchronization method is shown to be capable of providing high quality synchronization (HQS), which is essential for reliable communication. In this work, using this method, a secure digital communication system is proposed. The well known piece-wise linear 1-D map such as tent map and Bernoulli shift map are used for this study. Since the information is dynamically …

Development And Delivery Of Coursework: The Legal/Regulatory/Policy Environment Of Cyberforensics, John W. Bagby, John C. Ruhnka

Journal of Digital Forensics, Security and Law

This paper describes a cyber-forensics course that integrates important public policy and legal issues as well as relevant forensic techniques. Cyber-forensics refers to the amalgam of multi-disciplinary activities involved in the identification, gathering, handling, custody, use and security of electronic files and records, involving expertise from the forensic domain, and which produces evidence useful in the proof of facts for both commercial and legal activities. The legal and regulatory environment in which electronic discovery takes place is of critical importance to cyber-forensics experts because the legal process imposes both constraints and opportunities for the effective use of evidence gathered through …