Bragg Grating
Mostrando 1-12 de 30 artigos, teses e dissertações.
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1. Case study of muscle fatigue in parafunctional patient using occlusal device with fiber Bragg grating sensors
Abstract This case study describes a new method using a fiber optic Bragg grating sensor to determine muscle fatigue in a patient wearing a resilient occlusal device for the treatment of bruxism symptoms. Four tasks performed at maximum bite force induced rapid exhaustion for the analysis of fatigue. The results show that it is possible to obtain a better un
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2018-06
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2. Solving the inverse scattering problem with differential evolution: an experimental validation
Abstract This work shows the experimental validation of a method developed for determining the strain profile applied to a fiber Bragg grating by solving the inverse scattering problem. The non-uniform strain profile is recovered by formulating an optimization problem, solved with an algorithm based on differential evolution. The method has proved to be able
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2018-06
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3. Influence of temperature on the refractive index sensitivities of fiber Bragg gratings refractometers
Abstract Effect of cross-sensitivity between temperature and refractive index (RI) was studied using an optical sensor based on Bragg grating inscribed in an etched multi-mode fiber (MMF). RI sensitivities of different modes were used to obtain a linear response and temperature dependence in water:glycerin solutions. Results pointed out that the absolute ave
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-04
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4. Analysis of Thermo-Mechanical Stress in Fiber Bragg Grating Used for Hydro-Generator Rotor Temperature Monitoring
Abstract Fiber Bragg gratings (FBGs) offer new possibilities to monitor accurately the rotor temperature. Dozens of sensors can be mounted in series in a single fiber and used to measure the temperature in several points of the rotor winding. Such sensors installed directly on the rotor winding surface are thermally isolated from the cooling air by a silicon
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-04
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5. Long Period Bragg Grating in Coaxial Transmission Lines
This work shows the utilization of a coaxial cable for the fabrication of a long period Bragg grating. The grating is fabricated removing the dielectric in short pieces of the cable so that the discontinuities account for the variation in the medium refractive index. Simulated and experimental results of the grating resonances are shown as a function of the
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2015-06
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6. Etched FBG written in multimode fibers: sensing characteristics and applications in the liquid fuels sector
AbstractIn this work, a refractometric fiber sensor for the liquid fuels sector is described. The use of etched FBGs produced in multimode fibers is proposed to overcome the drawbacks associated with sensing high refractive index samples employing fiber transducers. The transducer sensitivity can be tailored by adjusting the final diameter of the etched Brag
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2015-06
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7. Hardware embedded fiber sensor interrogation system using intensive digital signal processing
The description of an interrogation system for fiber Bragg grating sensors is reported. The full implementation in hardware of the required signal processing is proposed and made publicly available. The hardware description is implemented in a field programmable gate array (FPGA) development kit and the processing units allow one to control an optoelectronic
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2014-12
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8. A technique to package Fiber Bragg Grating Sensors for Strain and Temperature Measurements
This paper reports an effective method of packaging a fiber Bragg grating (FBG) for the simultaneous measurement of temperature and strain. The technique consists of embedding two fiber Bragg grating sensors inside a polymeric material with different geometrical characteristics. The mechanical and thermal characterizations of the optical transducer were perf
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-12
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9. Estudo do desempenho do Multiplexador/Demultiplexador add/dropbaseado na configuraÃÃo do InterferÃmetro de Michelson de fibras Ãpticas para aplicaÃÃes em sistemas OTDMA e OCDMA / Study the performance of the multiplexer/demultiplexer add/drop based on the Michelson interferometer configuration for fiber for applications in optical systems OTDMA and OCDMA
Neste trabalho, alÃm dos capÃtulos que envolvem a teoria e definiÃÃes, foi basicamente divido em trÃs estudos: Primeiro (capÃtulo 4), apresentamos uma investigaÃÃo numÃrica do desempenho de um filtro passa-banda totalmente Ãptico composto por um acoplador direcional duplo seguido de duas grades de Bragg simetricamente iguais gravadas nos seus braÃ
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 02/03/2012
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10. Acopladores de cristais fotÃnicos e acesso mÃltiplo por divisÃo de cÃdigo Ãptico (OCDMA) com pulsos ultracurtos em fibras de Bragg / Photonic crystals couplers and optical code division multiple access (OCDMA) with optical ultra-short pulses in linear fiber Bragg gratings
This paper presents numerical simulation studies of propagation/switching of ultra-short pulses in photonic crystal couplers and Optical Code Division Multiple Access (OCDMA) using Fiber Bragg Grating (FBG). For coding were obtained analytically Gold codes. In the analysis of photonic crystal couplers (microstructured) investigated the properties of the prop
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/02/2012
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11. Performance analysis of peak tracking techniques for fiber Bragg grating interrogation systems
In this paper, we propose a spectral correlation-based technique for tracking the wavelength shift of a fiber Bragg grating. We compared this approach, by means of a Monte Carlo numerical simulation, to the typical peak tracking techniques applied in classic interrogation systems. As result, we obtained a considerable gain in terms of noise tolerance (about
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2012-12
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12. MONITORING CORROSION DEFECTS IN PLANAR STRUCTURES WITH FIBER BRAGG GRATING SENSORS / MONITORAÇÃO DE DEFEITOS POR CORROSÃO EM ESTRUTURAS PLANAS UTILIZANDO SENSORES A REDE DE BRAGG
O foco do presente trabalho é a detecção e o monitoramento de defeitos tais como perda de espessura por corrosão ou dano produzido por impacto em painéis metálicos planos. O sistema proposto emprega sensores de deformação a fibra óptica baseados em redes de Bragg, que possuem alta capacidade de multiplexação. O campo de deformações produzido na
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 05/10/2011