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Articles 4081 - 4110 of 4850

Full-Text Articles in Engineering

Contractor Variability In Construction Of Cement Treated Base Layers, Maile Anne Rogers Jul 2006

Contractor Variability In Construction Of Cement Treated Base Layers, Maile Anne Rogers

Theses and Dissertations

The primary purposes of this research were to identify construction factors most correlated to specific mechanical properties of cement-treated base (CTB) layers and to determine which construction factors exhibit comparatively high variability within individual construction sections of the two pavement reconstruction projects included in this study. In addition, differences between construction sections tested in this research were evaluated. The research focused on the construction of CTB layers in two pavement reconstruction projects in northern Utah, one along Interstate 84 (I-84) near Morgan and one along U.S. Highway 91 (US-91) near Richmond. The significant predictor variables associated with California bearing ratio …

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Microwave Remote Sensing Of Saharan Ergs And Amazon Vegetation, Haroon Stephen Jul 2006

Microwave Remote Sensing Of Saharan Ergs And Amazon Vegetation, Haroon Stephen

Theses and Dissertations

This dissertation focuses on relating spaceborne microwave data to the geophysical characteristics of the Sahara desert and the Amazon vegetation. Radar and radiometric responses of the Saharan ergs are related to geophysical properties of sand formations and near surface winds. The spatial and temporal variability of the Amazon vegetation is studied using multi-frequency and multi-polarization data. The Sahara desert includes large expanses of sand dunes called ergs that are constantly reshaped by prevailing winds. Radar backscatter measurements observed at various incidence and azimuth angles from the NASA Scatterometer (NSCAT), the ERS scatterometer (ESCAT), the SeaWinds scatterometer aboard QuikScat (QSCAT), and …

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Incorporating Wireless Power Transfer In An Led Lighting Application, Jonathan S. Shipley Jul 2006

Incorporating Wireless Power Transfer In An Led Lighting Application, Jonathan S. Shipley

Theses and Dissertations

There are various situations in which electrical energy is desired but cannot by conveniently supplied. Since the days of Hienrich Hertz and Nikola Tesla, scientists have tried to solve this problem using different methods of wireless power transfer. Today, wireless power transfer has only been commercially demonstrated at small distances through use of induction. This thesis demonstrated the transfer of wireless power at relatively large distances through radio frequencies in the development of a prototype for a commercial product - a wireless household lamp.

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A Solution For Commodity Field Hauling With Self-Unloading Semi-Trailers, Lee Pagens Wilkerson Jul 2006

A Solution For Commodity Field Hauling With Self-Unloading Semi-Trailers, Lee Pagens Wilkerson

Theses and Dissertations

Commodity hauling of bulk goods is a growing enterprise that has expanded from hauling agricultural products to hauling many other bulk products. Commodity trailers are used to haul agricultural products from storage facilities to processing plants. These trailers are designed for highway use but are frequently required to work in field conditions as well. In many cases this environment overstresses these trailers and results in permanent irreparable damage. In addition to the structural problems of these trailers, the current systems for unloading the bulk produce from these trailers have serious inadequacies. While functional, the currently used chain and non-chain driven …

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Development Of An Index For Concrete Bridge Deck Management In Utah, Ellen T. White Jul 2006

Development Of An Index For Concrete Bridge Deck Management In Utah, Ellen T. White

Theses and Dissertations

The purpose of this research was to develop a new index for concrete bridge deck management in Utah. Data were collected in the summer of 2005 from 15 concrete bridge decks in the vicinity of Salt Lake City. The decks ranged from 2 to 21 years in age and were all constructed using epoxy-coated rebar. Visual inspection, sounding, Schmidt hammer testing, half-cell potential testing, and chloride concentration testing were performed on six 6-ft by 6-ft test areas randomly distributed within the single lane closed to traffic on each deck, and testing protocols followed American Society for Testing and Materials standards …

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Numerical Modeling Of Blast-Induced Liquefaction, Wayne Yeung Lee Jul 2006

Numerical Modeling Of Blast-Induced Liquefaction, Wayne Yeung Lee

Theses and Dissertations

A research study has been conducted to simulate liquefaction in saturated sandy soil induced by nearby controlled blasts. The purpose of the study is to help quantify soil characteristics under multiple and consecutive high-magnitude shock environments similar to those produced by large earthquakes. The simulation procedure involved the modeling of a three-dimensional half-space soil region with pre-defined, embedded, and strategically located explosive charges to be detonated at specific time intervals. LS-DYNA, a commercially available finite element hydrocode, was the solver used to simulate the event. A new geo-material model developed under the direction of the U.S. Federal Highway Administration was …

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Design Of A Linear Ultrasonic Piezoelectric Motor, Scott L. Sharp Jul 2006

Design Of A Linear Ultrasonic Piezoelectric Motor, Scott L. Sharp

Theses and Dissertations

A new geometrically unique ultrasonic motor (USM) was designed using finite element modeling (FEM). A USM operates by vibrating a drive tip in an elliptical motion while it is in periodic contact with a driven surface. Piezoelectric elements are used to create the elliptical motions and are driven near a resonant frequency to create the needed displacements for the motor to operate. An idea for a motor frame was conceived that consisted of an arch, a center ground, and two piezoelectric elements connected to the center ground. End caps were added between the frame and the piezoelectric elements to reduce …

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A Study Of Home Builder Advertising For Smart Home Technologies, Jared Don Bingham Jul 2006

A Study Of Home Builder Advertising For Smart Home Technologies, Jared Don Bingham

Theses and Dissertations

The purpose of this research is to discover if home builders along the Wasatch Front in Utah are advertising smart home technologies. Research was conducted by a review of the display advertisements placed in the Saturday and Sunday editions of The Deseret Morning News/Salt Lake Tribune from March 4, 2006 through April 1, 2006. An internet search for smart home terminology was performed on the web sites of home builders advertising in The Deseret Morning News/Salt Lake Tribune. A review of the display advertisements for the Deseret Morning News/Salt Lake Tribune revealed that home builders are not using that medium …

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Random City Generator Technical Report, Brandon Call Jul 2006

Random City Generator Technical Report, Brandon Call

Faculty Publications

The Brigham Young University (BYU) Multiple Agent Intelligent Coordination and Control (MAGICC) research lab researchs many aspects of small unmanned air vehicles (UAV). To facilitate this research, students have created a UAV simulator called Aviones. In order to increase the capability of Aviones to simulate an urban environment, the ability to draw buildings, streets and vehicles have been added. This document outlines how cities are created and how a researcher can use them in conjunction with Aviones.

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Arq Techniques For Mimo Communication Systems, Zhihong Ding Jul 2006

Arq Techniques For Mimo Communication Systems, Zhihong Ding

Theses and Dissertations

Multiple-input multiple-output (MIMO) communication systems employ multiple antennas at the transmitter and the receiver. Multiple antennas provide capacity gain and/or robust performance over single antenna communications. Traditional automatic-repeat-request (ARQ) techniques developed for single-input single-output (SISO) communication systems have to be modified in order to be employed in MIMO communication systems. In this dissertation, we propose and analysis some ARQ techniques for MIMO communication systems. The basic retransmission protocols of ARQ, stop-and-wait (SW-ARQ), go-back-$N$ (GBN-ARQ), and selective repeat (SR-ARQ), designed for SISO communication systems are generalized for parallel multichannel communication systems. The generalized ARQ protocols seek to improve the channel utilization …

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Operational Amplifier Bandwidth Extension Using Negative Capacitance Generation, Adrian P. Genz Jul 2006

Operational Amplifier Bandwidth Extension Using Negative Capacitance Generation, Adrian P. Genz

Theses and Dissertations

A need for high bandwidth operational amplifiers, or op-amps, exists for certain applications. This need requires research in the area of op-amp bandwidth extension. The proposed method of this thesis uses Negative Capacitance Generation (NCG), which involves using the Miller effect to generate an equivalent negative capacitance at a given node in a circuit, to extend the bandwidth of an op-amp. This is accomplished by first applying NCG to the second stage of an op-amp, in which the op-amp has been compensated using Single Capacitor Miller Compensation (SCMC). Next, the Miller capacitor used to compensate the op-amp can be reduced …

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Seu-Induced Persistent Error Propagation In Fpgas, Keith S. Morgan Jul 2006

Seu-Induced Persistent Error Propagation In Fpgas, Keith S. Morgan

Theses and Dissertations

This thesis introduces a new way to characterize the dynamic SEU cross section of an FPGA design in terms of its persistent and non-persistent components. An SEU in the persistent cross section results in a permanent interruption of service until reset. An SEU in the non-persistent cross section causes a temporary interruption of service, but in some cases this interruption may be tolerated. Techniques for measuring these cross sections are introduced. These cross sections can be measured and characterized for an arbitrary FPGA design. Furthermore, circuit components in the non-persistent and persistent cross section can statically be determined. Functional error …

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Decentralized Cooperative Aerial Surveillance Using Fixed-Wing Miniature Uavs, Randal Beard, Derek Kingston, Timothy W. Mclain, Derek Nelson Jul 2006

Decentralized Cooperative Aerial Surveillance Using Fixed-Wing Miniature Uavs, Randal Beard, Derek Kingston, Timothy W. Mclain, Derek Nelson

Faculty Publications

Numerous applications require aerial surveillance. Civilian applications include monitoring forest fires, oil fields and pipelines, and tracking wildlife. Applications to homeland security include border patrol and monitoring the perimeter of nuclear power plants. Military applications are numerous. The current approach to these applications is to use a single manned vehicle for surveillance. However, manned vehicles are typically large and expensive. In addition, hazardous environments and operator fatigue can potentially threaten the life of the pilot. Therefore, there is a critical need for automating aerial surveillance using unmanned air vehicles (UAVs). This paper gives an overview of a cooperative control strategy …

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Compact And Low Loss Silicon-On-Insulator Rib Waveguide 90° Bend, Yusheng Qian, Seunghyun Kim, Jiguo Song, Gregory P. Nordin, Jianhua Jiang Jun 2006

Compact And Low Loss Silicon-On-Insulator Rib Waveguide 90° Bend, Yusheng Qian, Seunghyun Kim, Jiguo Song, Gregory P. Nordin, Jianhua Jiang

Faculty Publications

A compact and low loss silicon-on-insulator rib waveguide 90° bend is designed and demonstrated. An interface realized by a trench filled with SU8 at the corner of a waveguide bend effectively reflects incoming light through total internal reflection (TIR). In order to accurately position the SU8-filled trench relative to the waveguide and reduce sidewall roughness of the interface, electron beam lithography (EBL) is employed while inductively coupled plasma reactive ion etching (ICP RIE) is used to achieve a vertical sidewall. The measured loss for TE polarization is 0.32 dB ± 0.02 dB/bend at a wavelength of 1.55 µm.

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Evaluation Of The Effectiveness Of Blank-Out Overhead Dynamic Advance Warning Signal Systems, Ryan Peterson Jun 2006

Evaluation Of The Effectiveness Of Blank-Out Overhead Dynamic Advance Warning Signal Systems, Ryan Peterson

Theses and Dissertations

Advance warning signals installed upstream of a high-speed signalized intersection (HSSI) warn motorists of impending signal changes in an effort to reduce the frequency of red-light running (RLR) and crashes. A new advance warning signal design was tested on an approach to an HSSI in Utah to study the effects of the modified design on motorist behavior. The new design utilized an overhead dynamic blank-out sign and flashers. A state-of-the-art digital wave radar evaluation system was installed at the study site to collect continuous data of vehicle speeds and RLR events by a non-intrusive method. Crash data were collected from …

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Effect Of Stay-In-Place Metal Forms On Performance Of Concrete Bridge Decks, Stephen Litster Frost Jun 2006

Effect Of Stay-In-Place Metal Forms On Performance Of Concrete Bridge Decks, Stephen Litster Frost

Theses and Dissertations

The objectives of this research were to investigate the effect of stay-in-place metal forms (SIPMFs) on the performance of concrete bridge decks in Utah. The research program included six bridge decks with SIPMFs and six decks without SIPMFs, which were all located within the Interstate 215 corridor in the vicinity of Salt Lake City, Utah, and therefore subject to similar traffic loading, climatic conditions, and maintenance treatments, including applications of deicing salts during winter months. All of the tested decks were constructed between 1984 and 1989 using epoxy-coated rebar. Several tests were performed at each of six locations on each …

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Payback Information: It's Effect On Home Buyers Regarding Energy Efficiency, Steven E. Sparti Jun 2006

Payback Information: It's Effect On Home Buyers Regarding Energy Efficiency, Steven E. Sparti

Theses and Dissertations

This study was conducted to find out how payback analysis would affect consumer decision making with regards to home energy efficient upgrade packages. Three different home plans were obtained from a local builder and seven different energy efficient packages were created. Using Hot2000 the heating and cooling loads were calculated for each building, with each energy efficient package, in each of the four major cardinal directions. The averages were taken and the payback information was calculated. The payback information included the increased cost of the package, the increase in the mortgage payment, the annual savings from heating and cooling bills, …

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Assessing The Safety Impacts Of Access Management Techniques, Jeff S. Lewis Jun 2006

Assessing The Safety Impacts Of Access Management Techniques, Jeff S. Lewis

Theses and Dissertations

Access management techniques such as raised median installation and driveway consolidation improve safety conditions for motorists. Several locations where these access management techniques have been installed in the state of Utah were selected for analysis of the safety impacts. Although crash rates were not necessarily reduced as a result of the access management techniques, other safety improvements were observed. The raised medians generally reduced the more serious types of collisions, which resulted in a decrease in the severity of crashes. The fatality rates generally decreased as crashes became less severe. Because fatalities and the overall severity of crashes decreased, the …

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Development Of A Variational Part Model Using In-Process Dimensional Measurement Error, Shane A. Carlson Jun 2006

Development Of A Variational Part Model Using In-Process Dimensional Measurement Error, Shane A. Carlson

Theses and Dissertations

To improve the geometric accuracy of CNC machined parts, dynamic machining errors due to on-line disturbances (tool deflection, tool wear, heat deformation, etc.) should be accounted for in some manner. Unless these on-line disturbances are properly handled, it is obvious that a high degree of geometric accuracy is difficult to achieve. Many attempts have been made to compensate for these on-line disturbances such as the development of engineering models; however, the models are not adequate enough for reflecting the real phenomenon and are dependent on continuous process monitoring using a variety of sensors. Closed-loop process control is a scheme for …

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Black Liquor Droplet Combustion And Modeling, Warren Benjamin Roberts Jun 2006

Black Liquor Droplet Combustion And Modeling, Warren Benjamin Roberts

Theses and Dissertations

Black liquor is an intermediate product of pulp production. Recovery boilers process black liquor to recover the inorganic material for recycling in the mill and to generate electricity and steam for the paper mill. Black liquor droplet combustion rates and mechanisms dictate many aspects of recovery boiler performance. This investigation documents new experimental data on single droplet pyrolysis and combustion in a laboratory furnace that mimics many of the essential features of commercial boilers (temperature, composition, droplet size, etc.). These experiments monitored single droplets placed on a thermocouple wire and suspended from a mass balance. Simultaneous video images and pyrometry …

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Poisoning And Sulfation On Vanadia Scr Catalyst, Xiaoyu Guo Jun 2006

Poisoning And Sulfation On Vanadia Scr Catalyst, Xiaoyu Guo

Theses and Dissertations

Deactivation of titania-supported vanadia commercial SCR catalysts exposed to flue gases from both coal and coal-biomass co-firing boilers were investigated. BET surface area and average pore diameter measurements on both fresh and exposed commercial catalyst samples indicated pore plugging occurred to exposed catalyst samples. ESEM analyses showed fouling on catalyst surface, and poison deposition on both catalyst surface and inner pores. Activity assessments of commercial monolith catalysts with various exposures (time and fuel type) indicated that catalyst deactivation involves fouling, pore plugging, and poisoning. Different mechanisms may dominate depending on exposure time, catalyst properties, and combustion environment. Better controlled lab-scale …

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Compliant Mechanism Suspensions, Timothy Melvin Allred Jun 2006

Compliant Mechanism Suspensions, Timothy Melvin Allred

Theses and Dissertations

This thesis has explored the use of compliant mechanisms in vehicle suspension systems, specifically where a compliant mechanism acts as part of the wheel locating mechanism and as the energy storage element. A compliant mechanism has the potential of reducing part count, joints, and manufacturing and assembly costs of a suspension system. Fatigue failure has been found to be a limiting design constraint which competes with space and weight constraints. Controlling wheel motion in response to control forces has also been shown to be an important functional requirement for a compliant suspension system. Vehicle applications that are best suited for …

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Effect Of Co On No And N2O Conversions In Nonthermal Argon Plasma, Gui-Bing Zhao, Morris D. Argyle, Maciej Radosz Jun 2006

Effect Of Co On No And N2O Conversions In Nonthermal Argon Plasma, Gui-Bing Zhao, Morris D. Argyle, Maciej Radosz

Faculty Publications

200-600 ppm of CO inhibit NO conversion in nonthermal Ar plasma, but do not produce ⁠N2O. However, 1.01% of CO has no effect on NO conversion, but produces ⁠N2O. In general, N2O conversion in Ar plasma decreases with increasing CO concentration. These experimental results cannot be explained by charge transfer reactions of Ar+⁠. Selectivity analysis of all excited states of Ar possibly contributing to NOx conversion without and with CO suggests that only Ar(3P2) contributes to NOx conversion and CO dissociation. A kinetic model of 43 …

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Vector Field Path Following For Small Unmanned Aerial Vehicles, Derek R. Nelson, D. Blake Barber, Timothy W. Mclain, Randal W. Beard Jun 2006

Vector Field Path Following For Small Unmanned Aerial Vehicles, Derek R. Nelson, D. Blake Barber, Timothy W. Mclain, Randal W. Beard

Faculty Publications

This paper presents a new method for unmanned aerial vehicle path following using vector fields to represent desired ground track headings to direct the vehicle onto the desired path. The key feature of this approach is that ground track heading error and lateral following error approach zero asymptotically even in the presence of constant wind disturbances. Methods for following straight-line and circularorbit paths, as well as combinations of straight lines and arcs, are presented. Experimental results validate the effectiveness of this path following approach for small air vehicles flying in high-wind conditions.

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Vision-Based Target Localization From A Fixed-Wing Miniature Air Vehicle, Joshua D. Redding, Timothy W. Mclain, Randal W. Beard, Clark N. Taylor Jun 2006

Vision-Based Target Localization From A Fixed-Wing Miniature Air Vehicle, Joshua D. Redding, Timothy W. Mclain, Randal W. Beard, Clark N. Taylor

Faculty Publications

This paper presents a method for localizing a ground-based object when imaged from a small fixed-wing unmanned aerial vehicle (UAV). Using the pixel location of the target in an image, with measurements of UAV position and attitude, and camera pose angles, the target is localized in world coordinates. This paper presents a study of possible error sources and localization sensitivities to each source. The localization method has been implemented and experimental results are presented demonstrating the localization of a target to within 11 m of its known location.

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Cement Stabilization Of Aggregate Base Materials Blended With Reclaimed Asphalt Pavement, Ashley Vannoy Brown May 2006

Cement Stabilization Of Aggregate Base Materials Blended With Reclaimed Asphalt Pavement, Ashley Vannoy Brown

Theses and Dissertations

The purpose of this research was to investigate the effects of reclaimed asphalt pavement (RAP) content and cement content on the strength and durability of recycled aggregate base materials. Specifically, the unconfined compressive strength (UCS) and final dielectric value in the Tube Suction Test (TST) were measured in a full-factorial experimental design including five RAP contents, five cement contents, and three replicate specimens of each possible treatment. Specimen mixtures consisted of 0, 25, 50, 75, or 100 percent RAP and 0.0, 0.5, 1.0, 1.5, or 2.0 percent Type I/II Portland cement. Both the RAP and base materials were sampled from …

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A Study Of Model Integration In Conjunction With The Extensible Model Definition Format, Melanie A. Fife May 2006

A Study Of Model Integration In Conjunction With The Extensible Model Definition Format, Melanie A. Fife

Theses and Dissertations

A considerable amount of research has been done to connect or integrate separate numerical models. The Environmental Modeling Research Laboratory (EMRL) has developed a generic file format, the eXtensible Model Data Format (XMDF). One of the objectives of the XMDF project is to facilitate the spatial interpolation and data-sharing necessary when linking models. The objective of this research is to investigate how model linking capabilities can be added to the XMDF by defining a Model Linkage Object (MLO) that is compatible with current model linking frameworks. A potential design for an MLO is defined in this thesis after a detailed …

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Fpga-Based Experiment Platform For Hardware-Software Codesign And Hardware Emulation, Yajuvendra Nagaonkar May 2006

Fpga-Based Experiment Platform For Hardware-Software Codesign And Hardware Emulation, Yajuvendra Nagaonkar

Theses and Dissertations

An FPGA-based experiment platform for hardware-software codesign experiments was developed. The proposed platform would be used by an engineer who can be affiliated with academia, research or industry for codesign experiments or hardware emulation. The platform utilizes a combination of a microcontroller and a FPGA device to enable sufficient flexibility in exploring the design space to implement codesign experiments. The FPGA device operation is integrated with that of the microcontroller to provide an overall embedded solution for codesign experimentations. It is anticipated that the platform will be used in academia for educating the students the concepts of computer architecture and …

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An Xyz Micromanipulator With Three Translational Degrees Of Freedom, Kimberly A. Jensen, Craig P. Lusk, Larry L. Howell May 2006

An Xyz Micromanipulator With Three Translational Degrees Of Freedom, Kimberly A. Jensen, Craig P. Lusk, Larry L. Howell

Faculty Publications

This paper introduces a three degree of freedom XYZ Micromanipulator (XYZM) that is fabricated in the x-y plane and positions components in the x, y, and z directions using three independent linear inputs. The mechanism positions components on a platform using three legs, each composed of a slider mechanism and a parallelogram mechanism.

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Compact Integrated Depolarizer For Interferometric Fiber Optic Gyroscopes, Lixia Li, Jaime Cardenas, Jianhua Jiang, Gregory P. Nordin May 2006

Compact Integrated Depolarizer For Interferometric Fiber Optic Gyroscopes, Lixia Li, Jaime Cardenas, Jianhua Jiang, Gregory P. Nordin

Faculty Publications

We propose an integrated waveguide depolarizer for use in interferometric fiber optic gyroscopes (IFOGs) with single-mode fiber coils. The integrated waveguide depolarizer is based on a Mach-Zender interferometer with polarizing beamsplitters. A waveguide polarizing beamsplitter is designed using multiple air trench structures oriented at the Brewster angle. We also analyze the effect of component imperfections on the degree of polarization achievable with an integrated waveguide depolarizer.

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