Дисертації з теми "Fiber optic instrument"
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Pierce, Mary E. "Engineering a fiber-optic implantable cardiovascular biosensor /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1422954.
Повний текст джерелаHamner, Vincent N. "A fiber optic polarimeter for use in chemical analysis." Thesis, Virginia Tech, 1990. http://hdl.handle.net/10919/42892.
Повний текст джерелаPolarimetry, as applied to chemical analysis, deals with the
determination of the extent and direction that an optically
active chemical species will rotate incident linearly
polarized light. Although well developed for physical
sensing, the technique of fiber optic polarimetry for
chemical sensing remains in its infancy. This thesis is
concerned with the design and development of an optical fiber
polarimeter which measures the optical rotation of linearly
polarized light that occurs in a sensing region between two
multi-mode optical fibers. Over short distances, the
polarization preserving capabilities of large-core multi-mode
optical fibers were investigated. Polarimetric analyses were
performed using sucrose and quinine hydrochloride. The
instrument has a resolution of O.O8·, and is an excellent
platform for an LC or FIA detector. Its more intriguing
future lies in evanescent field sensor applications and
studies of chiroptical surface interactions.
Master of Science
Sakamoto, João Marcos Salvi. "Laser ultrasonics system with a fiber optic angular displacement sensor." Instituto Tecnológico de Aeronáutica, 2012. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=2146.
Повний текст джерелаДенисов, Микола Олександрович. "Підвищення ефективності незображуючих волоконно- оптичних систем для мінімально інвазивної клінічної медицини". Doctoral thesis, Київ, 2016. https://ela.kpi.ua/handle/123456789/16317.
Повний текст джерелаBiazon, Filho Alcino José. "Nova técnica de malha fechada para estabilização do ponto de operação de interrogadores de sensores com grade de bragg em fibras ópticas." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260881.
Повний текст джерелаTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: Sensores de fibra óptica são imunes à interferência eletromagnética (EMI), e são uma excelente escolha para ser usado em ambientes eletricamente ruidosos aplicações em sensoriamento remoto, incluindo aeroespacial, ferroviário equipamentos de segurança militar e em linhas de alta tensão. Outras vantagens incluem o fato de que eles são compactos, leves e os sinais de medição podem ser transmitidos a distâncias muito grandes (da ordem de km). Os interrogadores convencionais para redes de Bragg (FBG) do sensor são equipamentos de custo elevado e não pode ser utilizado em aplicações de baixo custo. Neste trabalho é apresentada uma nova técnica de interrogação robusta e de baixo custo que apresenta uma boa precisão. A técnica, que utiliza um circuito de retroalimentação eletrônico para estabilizar o ponto de operação DC das grades de Bragg, permite a medição simultânea de ambos sinais AC e DC. Um protótipo do interrogador proposto foi projetado e implementado. A técnica exige apenas três componentes ópticos: um laser distribuído, um acoplador óptico e um fotodiodo. O interrogador foi testado com sucesso em uma aplicação de DC (medição de temperatura) e uma aplicação AC (medição de corrente elétrica). Os resultados experimentais mostraram que o controle eletrônico em malha fechada pode controlar o ponto de operação da FBG com uma precisão de ± 2 ppm
Abstract: Fiber optic sensors are immune to electromagnetic interference (EMI), and are an excellent choice for being used in electrically noisy environments sensing applications, including aerospace, rail, military security equipment and in high voltage power lines. Other advantages include the fact that they are compact, lightweight and the measured signals can be transmitted at very large distances (of the order of kilometers). The conventional interrogators for Fiber Bragg Gratings (FBG) sensor are high cost equipment and cannot be used in low cost applications. In this work it is presented a novel robust and low cost interrogation technique that presents good accuracy. The technique, which uses an electronic feedback loop to stabilize the DC operating point of the Bragg gratings, allows the simultaneous measurement of both AC and DC signals. A prototype of the proposed interrogator was designed and implemented. The technique requires only three optical components: a Distributed Feedback Laser, an optical coupler and one photodiode. The interrogator has been successfully tested in a DC application (temperature measurement) and an AC application (electrical current measurement). Experimental results showed that the electronic feedback loop can control the operation point of the FBG with a precision of ±2 ppm
Doutorado
Eletrônica, Microeletrônica e Optoeletrônica
Doutor em Engenharia Elétrica
Jovanovic, N., N. Cvetojevic, C. Schwab, B. Norris, J. Lozi, S. Gross, C. Betters, et al. "Efficiently feeding single-mode fiber photonic spectrographs with an extreme adaptive optics system: on-sky characterization and preliminary spectroscopy." SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622807.
Повний текст джерелаDamin, Craig Anthony. "Instrument Development and Application for Qualitative and Quantitative Sample Analyses Using Infrared and Raman Spectroscopies." Miami University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=miami1385774823.
Повний текст джерелаMartinod, Marc-Antoine. "Développement et exploitation scientifique d’un nouvel instrument interférométrique visible en optique guidée." Thesis, Université Côte d'Azur (ComUE), 2018. http://www.theses.fr/2018AZUR4215/document.
Повний текст джерелаLong baseline visible interferometry in astronomy is an observing technique which allows to get insights of an object with an outstanding angular resolution, unreachable with single-dish telescope. Interferometric measurements with ground-based instrumentation are currently limited in sensitivity and precision due to atmospheric turbulence. However, the new astrophysical needs, particularly the determination of fundamental parameters or the study of the closed environment and the surface of the stars, require to observe fainter objects with a better precision than now in visible interferometry. Ought to overcome the atmospheric turbulence, multispeckle interferometry has been developed by adapting speckle imaging technics used on single-dish telescope. Today, in order to improve the performance of the future combiners, instrumentation progresses to the use of a new generation detector called EMCCD, and the use of optical fibers which are coupled with adaptive optics. This path is chosen thank to the success of the use of the adaptive optics with the fringe tracking in the infrared interferometry in 2017 (Gravity Collaboration et al. 2017), in order to compensate turbulence. FRIEND prototype (Fibered and spectrally Resolved Interferometer - New Design) has been designed to characterize and estimate the performance of such a combination of technologies, in the visible spectral band. The improvement of the precision of the measurements from interferometric instruments is due to optical fibers and the dynamical range of the EMCCD. The counterpart of using the optical fibers is a loss in sensitivity due to a low injection rate of flux into the fibers because of the atmospheric turbulence. On the other hand, sensitivity is improved thanks to adaptive optics and EMCCDs. Indeed, adaptive optics increases the injection rate and EMCCDs can measure low fluxes. Lastly, FRIEND is a pathfinder for the future instrument SPICA which should recombine up to 6 telescopes (Mourard et al. 2017, 2018). Fringe-tracking aspects will have to be studied for SPICA; this topic is not dealt with in this thesis. In this work, I present the FRIEND prototype, which can recombine up to three telescopes and operates in the R band with dispersed fringes. It has Gaussian polarization-maintaining single mode optical fibers and an EMCCD. It is set up at the Center for High Angular Resolution Astronomy (CHARA), at Mount Wilson, in California. CHARA is currently being equipped with adaptive optics. I develop estimators of visibility modulus and closure phase, the data reduction software and an observing strategy. Thanks to that, I am able to show that adaptive optics improves the injection rate. I also demonstrate how important the stabilization of injection is to maximize the signal-to-noise ratio (SNR) per frame. Birefringence of the fibers decreases the performance of the instrument but we manage to compensate it. I show how such an instrument can measure low visibility with a better precision than now by developing and using a SNR model of FRIEND. Finally, FRIEND has entirely been tested on the known binary system ζ Ori A. These observations demonstrate how reliable and accurate the measurements of FRIEND are
Morana, Adriana. "Gamma-rays and neutrons effects on optical fibers and Bragg gratings for temperature sensors." Phd thesis, Université Jean Monnet - Saint-Etienne, 2013. http://tel.archives-ouvertes.fr/tel-01064993.
Повний текст джерелаLeite, Rogerio Lara. "Uma contribuição ao estudo e desenvolvimento de sensores de alta tensão baseados em fibras opticas." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260870.
Повний текст джерелаTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: Os sensores a fibra óptica são especialmente indicados para operarem em ambientes eletricamente ruidosos, uma vez que são imunes aos efeitos da interferência eletromagnética (EMI) encontrados nestes ambientes. Tal característica faz com que os sensores ópticos sejam altamente vantajosos para as aplicações nos sistemas de sensoreamento utilizados pelas empresas de energia elétrica. Este trabalho apresenta o desenvolvimento de um protótipo de baixo custo de um sensor óptico de alta tensão com alta confiabilidade, que pode ser usado para monitorar o estado ou limiares de tensão em uma rede elétrica. Uma técnica de detecção do sinal através do sensoreamento com grades de Bragg é apresentada, fabricada e avaliada. Os resultados mostram que a técnica de detecção empregada, onde a amplitude ac do sinal da luz refletido é medida em um fotodiodo, mostra-se adequada para a aplicação em sensores de alta tensão. As medidas realizadas em um protótipo de sensor de alta tensão com fibra óptica com grade de Bragg indicam que o esquema de detecção desenvolvido é promissor, e pode ser usado para medir outros sinais dinâmicos que respondam a um esforço de pequena amplitude aplicado à fibra óptica. O protótipo desenvolvido permitiu a detecção de tensões variando na faixa de 143 V -60kY. É também apresentada uma nova técnica para estabilizar termicamente grades de Bragg com a temperatura, utilizando o sinal uma fibra extra, casada com a fibra do sensor, que através de um circuito de realimentação atua no elemento aquecedor/resfriador do laser semicondutor(thenno electrical cooler), para fazer com que o comprimento de onda do laser siga as variações da sintonia da grade de Bragg sensora, causadas por variações da temperatura. Esta técnica inovadora poderá ser utilizada para a compensação térmica de outros tipos de sensores com grade de Bragg, permitindo a fabricação de sensores de baixo custo e grande simplicidade de implementação
Abstract: Fiber optics sensors are specially indicated to operate in noisy electrical environments because they are immune to the effects of electromagnetic interference (EM!) found in these environrnents. Such characteristic makes these sensors highly advantageous to the applications in the measurement systems used by electrical energy companies. This work presents the development of a prototype of a high-voltage and a low cost optical sensor which is used to monitor the state or voltage threshold with a high reliability. A technique for the detection of fiber Bragg grating sensors signals was developed, presented and tested. The experimental results showed that the developed detection technique, where the ac amplitude of the signal result from the light reflection is measured with a photodiode is adequate for high voltage sensing applications. The prototype of the high voltage fiber Bragg sensor was tested and the measured results indicate that the technique can be used to detect any other dynarnic measurand which induces a small strain amplitude when applied to the fiber Bragg grating. The developed prototype detected voltages in the range from 143 V to 60 kV. It is also presented a new technique for obtaining temperature independent fiber Bragg gratings, using a feedback circuit which uses the signal detected from a matched fiber and generates a signal which actuates on the thermo electrical cooler of the semiconductor laser, modifying the laser' s output wavelength, in orer to accurate track the Bragg wavelength shifts caused by temperature variations. This novel technique can be used for the fabrication of simple and low-cost temperature compensated fiber Bragg grating sensors
Doutorado
Eletrônica, Microeletrônica e Optoeletrônica
Doutor em Engenharia Elétrica
Valle, Orero Jessica. "Dynamics and thermal behaviour of films of oriented DNA fibres investigated using neutron scattering and calorimetry techniques." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2012. http://tel.archives-ouvertes.fr/tel-00734670.
Повний текст джерелаHsiao, Kuang-Fu, and 蕭光甫. "Dental Fiber Optic the Grinding Instrument with System and Method." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/5arp95.
Повний текст джерела國立虎尾科技大學
機械與機電工程研究所
101
Large diameter (0.4~1.0mm) fiber termination is widely used in the gum related cares. However, cost-effective shaped fiber is not yet developed for high power (~5W) laser. In this study, we have demonstrated the feasibility of using two stepping motors with a patented axial movement (0.005mm increments) method. The key parameters are investigated using finite element modeling. The results show that larger fiber diameter with less number of feeding increments can damage the fiber during polishing process.
Lin, Nathan Ching. "Fiber-optic probe and bulk-optics Spectral Domain Optical Coherence tomography systems for in vivo cochlear mechanics measurements." Thesis, 2019. https://doi.org/10.7916/d8-xmhj-ap89.
Повний текст джерелаDu, Plessis Jan Harm. "An all-fibre laser distance measurement system utilising figure-eight fibre lasers with electro-optic amplitude modulation." Thesis, 2010. http://hdl.handle.net/10210/3417.
Повний текст джерелаThe aim of this project is to research the feasibility of an all-fibre laser distance measurement device that utilises a figure-eight fibre laser (F8L), in the nonlinear amplifying loop mirror (NALM) configuration, as a light source and implements pulse compression to improve the accuracy and signal-to-noise ratio of the system. A figure-eight fibre laser in the NALM configuration for use in a laser distance measurement device is described. The theory of fibre lasers is discussed, including mode-locking and Qswitching, and the characteristics of a NALM loop are analysed. By varying the length of the NALM loop from 500 m to 2000 m or inserting highly nonlinear dispersion shifted fibre, a variety of pulses in the picosecond to nanosecond range can be produced. The lengths of the pulses depend on the length of the NALM loop, the pump power and the setting of the polarisation controllers. The figure-eight fibre laser is pumped with a 980 nm laser diode up to 550 mA, which corresponds to 320 mW. Distance measurements are done with short unmodulated and long modulated pulses. Distance measurement with short unmodulated pulses is discussed only briefly and tested with a simple experiment. The focus of this project is distance measurement with long modulated pulses. A low autocorrelated binary sequence is modulated onto one of the long pulses produced by the figure-eight fibre laser by an electro-optic amplitude modulator. The long pulse gives the proposed system a good signal-to-noise ratio (SNR), while the modulation improves the accuracy. A Barker code of length 13 is proposed as modulation code because of its good autocorrelation properties. The Barker code will improve the accuracy 13-fold, with a corresponding increase in SNR. An electro-optic amplitude modulator is used to implement the modulation. The modulated long pulse is then sent to a target. After reflection, the signal is detected and cross-correlated to obtain the time-of-flight for the pulse. The code generation and cross-correlation are implemented with an FPGA via VHDL programming. The distance to a target can be calculated by knowing the time-of-flight and the speed of light in the propagation medium. In this project the resolution, single-shot precision, accuracy, linearity, repeatability and maximum unambiguous distance of the proposed all-fibre laser distance measurement device are examined.
Hsu, Shih-Chuan, and 許仕均. "Application of Fiber Optic Sensors and Microphones in the Ni-Ti Rotary Instruments to Monitor of Fatigue Fracture." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/00114348278140560252.
Повний текст джерела(8713962), James Ulcickas. "LIGHT AND CHEMISTRY AT THE INTERFACE OF THEORY AND EXPERIMENT." Thesis, 2020.
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