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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 45 for “"optical fiber sensors"”.
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Sapphire optical fiber sensors
Fiber optic sensors offer many advantages over conventional sensors, including; small size, low weight, high strength and durability. Standard silica optical fibers are limited by the material properties of silica. Temperatures above 700°C and other harsh environments are incompatible with standard …
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Innovative Plastic Optical Fiber Sensors
… thesis describes the development of new types of fiber optic sensors for the measurement of mechanical quantities such as displacement, vibration and acceleration. Also, it describes the realization of specific acquisition systems designed to interrogate the developed sensors. Since optical fibers …
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Concentric-core optical fiber sensors
… strain sensor which uses concentric core optical fiber waveguide as the sensing element. When this particular type of fiber is strained, a transfer of optical power occurs between propagating modes in the two concentric cylindrical cores of the fiber. This strain-induced redistribution of …
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Novel phase-modulated optical fiber sensors
Optical fiber systems have been developed during the past twenty-five years with primary applications in long distance, high speed digital information communication. Optical fiber sensors have also been developed over the past fifteen years for the nondestructive inspection and evaluation of …
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Optical fiber sensors for advanced civil structures
… is to develop, analyze, and implement optical fiber-based sensors for the nondestructive quantitative evaluation of advanced civil structures. Based on a comparative evaluation of optical fiber sensors that may be used to obtain quantitative information related to physical perturbations …
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Material process monitoring with optical fiber sensors
… of an effort to design a multi-functional fiber optic sensor which can be embedded in polymeric composite laminates for monitoring the degree of cure during its fabrication, as well as internal composite strains occurring post-cure.3 In short, this dual-purpose sensor combines the …
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Weighted sensitivity optical fiber sensors: theory and applications
… of conventional dual mode, elliptical-core, optical fiber sensors is investigated. To compliment the experimental results, a novel linearly polarized modal analysis of elliptical-core geometries is performed. The method numerically finds solutions of a waveguide equation described by Mathieu …
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Optical Path Length Multiplexing of Optical Fiber Sensors
Optical fiber sensor multiplexing reduces cost per sensor by designing a system that minimizes the expensive system components (sources, spectrometers, etc.) needed for a set number of sensors. The market for multiplexed optical sensors is growing as fiberoptic sensors are finding application in …
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Spread spectrum techniques for distributed multimeasurand optical fiber sensors
… solution to the urgency for distributed optical fiber sensors. These techniques are based on the properties of pseudorandom sequences that have triangular autocorrelation functions with peaks only at regions of no delay. This affords an opportunity to give the desired signal a power …
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Advances in elliptical-core two-mode optical fiber sensors
… the practicality of the elliptical-core two-mode optical fiber sensors for use in real-life applications are presented. The improvements include the development of insensitive lead fibers and an optical device which allows fringe counting at the output of the sensor. The insensitive leads …
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Applications of optical fiber sensors with thick metal coatings
Over the past decade, fiber optic strain sensors have begun to transition from use in laboratory research to commercial sector applications. This transition is somewhat hindered due to the high cost associated with many optical components required for fiber optic-based sensing systems. Multiplexing …
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Application of Optical Fiber Sensors for Quenching Temperature Measurement
… of technological advancement in the field of fiber optics, it is possible to measure the quenching temperature to a much higher degree of precision. Optical fiber sensors are capable of taking many more measurements along a fuel simulator length than thermocouples, which are restricted to …
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Controlled Fabrication System of Fabry-Perot Optical Fiber Sensors
The use of optical fiber sensors is increasing widely in industry, civil, medicine, defense and research. Among different categories of these sensors is the Extrinsic Fabry-Perot interferometer (EFPI) sensor which is inherently simple and requires only modest amount of interface electronics. These …
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Optical fiber sensors embedded in concrete structures : feasibility and durability studies
Thesis (Civ. E.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1996.
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Signal processing techniques for optical fiber sensors using white light interferometry
Conventional fiber optic interferometric sensors employing a monochromatic source prove to be inadequate for applications requiring absolute, real-time value of magnitude and direction of the applied perturbation. This limitation can be overcome by using a broadband light source to extract …
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Distributed-effect modal domain optical fiber sensors for flexible structure control
Recently, a new class of sensors has emerged which have scalar outputs derived from distributed measurements over a significant gauge length; these sensors are known as distributed-effect sensors. The most familiar example of a distributed-effect sensor is the piezoelectric laminate PVDF film; …
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Multiplexing of Extrinsic Fabry-Perot Optical Fiber Sensors for Strain Measurements
… can be caused by an earthquake. Conventional sensors are becoming obsolete in sensing for today's multistory buildings because they don't monitor the structural health of the guide rails. This sensing task falls into the fiber sensing niche market because of a fiber sensor's ability to be …
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Simultaneous measurement of strain and temperature using liquid core optical fiber sensors
A liquid core fiber sensor can be used to sense both strain and temperature simultaneously. This liquid core fiber sensor is comprised of a hollow core optical fiber filled with a liquid of a known index of refraction which is slightly higher than that of the silica tube which acts as the cladding. …
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Digital spectral analysis and adaptive processing techniques for phase modulated optical fiber sensors
… investigate new signal processing techniques for optical fiber sensors that utilize the phase information of the electromagnetic field. Research concentrated on Fourier transform spectroscopy as a means for capturing wavelength encoded information from the fiber sensor. Classical spectral analysis …
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The utilization of piezoelectric materials and optical fiber sensors for electric field detection
For many years, the use of fiber optic sensors for the measurement of strain, temperature and pressure has been widely investigated. Much less research has been directed towards the use of these sensors for measuring electric and magnetic fields. As existing field meters have conductive parts which …
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