Encontrados 10 documentos, a visualizar página 1 de 1
Remote Optical Monitor of Blood Oxygenation
D. R. Santos; R. J. O. Andrade; A L. J. Teixeira; C. A. C. Bastos; P. S. AndréPulse oximetry is a widely used technique in biomedical analyses. It enables monitoring the percentage of saturated hemoglobin and heart pulse in a noninvasive way.The mandatory permanence of patients in medical facilitiesdue to continuous measurements of blood oxygen saturationand cardiac pulse can be avoided by taking advantage of nowadays telecommunications technologies. This paperdescribes a pulse oximeter ...
Optimização eficiente do ganho espectral de amplificadores de Raman com bombage...
B. Neto; S. Stevan Jr.; R. Nogueira; A. L. J. Teixeira; M. J. N. Lima; P. S. AndréWe report the use of the Genetic Algorithm (GA) in the optimization of a distributed Raman amplifier spectralgain. The used methodology is based on the direct integrationof Raman propagation equations making use of the transfermatrix method, which ensue into a considerable reduction ofthe computation time. Pointing out an on/off Raman gain of10 dB, we develop a technique based in a combination of theGA with the...
Raman Amplifiers for Use in WDM Systems
D. B. M. Pereira; A. L. J. Teixeira; M. J. N. Lima; P. S. B. André; H. C. C. Fernandes; J. R. Ferreira da RochaIn this paper Raman Amplifiers (RAs) for Wavelength Division Multiplexed (WDM) fiber optic systems are analysed. We start by explaining the physical principles of this kind of amplification are explained, and the principal characteristics and advantages of using these amplifiers are enumerated.The technique of multiple pumping (MP) is studied aiming to obtain broadband amplifiers w...
Wideband Erbium-Doped Fiber Amplifier System Design Limitations due to Cband Si...
D. B. M. Pereira; A. L. J. Teixeira; M. J. N. Lima; P. S. B. André; J. R. Ferreira da RochaIn this paper we observe experimentally the effects of C-band pump light in the performances of an Lband Erbium-Doped Fiber Amplifier (EDFA). An amplifier for C+L-bands in a parallel configuration of two EDFAs is designed, and the inherent implications in its application to optical fiber communications systems. A new configuration is presented for decreasing the signal gain depende...
Comparação de desempenho de Amplificadores a Fibra Dopada com Érbio para difere...
S. L. Stevan Jr.; A. Pohl; A. L. J. Teixeira; Neste trabalho são comparados vários Amplificadores de Fibra Dopada com Érbio nos quais se varia os perfis índice de refracção da fibra dopada que os constitui. São analisadosquatro perfis. Numa primeira etapa são analisados os comportamentos dos diferentes perfis com mesma área denúcleo da fibra, e numa segunda etapa alter...
Thermally Tunable Bragg Grating Filtrers for Wavelength-Multiplexed Systems
M. J. N. Lima; O. Frazão; A. L. J. Teixeira; P. S. B. André; J. R. Ferreira da RochaIn this contribution we compare the thermal tuning capabilities of two type I gratings, considering an unloaded and a hydrogen-loaded fiber, and a type IIa grating. We further study their responses stability with temperature, analyzing their potential as optical filters in wavelength division multiplexing systems. We conclude that all of them have similar tuning efficiencies, howev...
Bragg Gratings with Enhanced Temperature Sustainability Written in a High- Germ...
M. J. N. Lima; R. N. Nogueira; J. C. C. Silva; A. L. J. Teixeira; P. S. B. André; J. R. F. da Rocha; J. H. Kalinowski; J. L. PintoIn this contribution we report the achievement offiber Bragg gratings exhibiting high temperaturesustainability, resultant from type IIA and a new abnormalexposition regimes, and compare their thermal stability withother gratings obtained from different growth mechanisms,namely type I and IA. It is expected that type IIA and thedesignated as abnormal gratings improve the reliability ofhigh-temperature grating-s...
Characterization of an Amplifier the Waveguide Erbium Doped
S. L. Stevan Jr.; F. Couto; P. André; P. Monteiro; A. L. J. Teixeira; Neste trabalho reportamos a caracterização e testede um amplificador de guia de onda dopado com Erbio(EDWA). As curvas de ganho e figura de ruído em função dapotência de entrada e em função do comprimento de ondaforam obtidas par um método por nós desenvolvido. Ascaracterísticas de largura de banda de ganho saturado efigura de ru&ia...
Dispersion modeling a dynamic chromatic dispersion compensator based on Bragg g...
B. Neto; M. J. N. Lima; A. L. J. Teixeira; R. N. Nogueira; J. L. Pinto; J. R. F. da Rocha; P. AndréWe report a method to realize tunable chromatic dispersion compensation based on chirped fiber Bragg gratings (CFBG). The changes on the CFBG dispersion are achieved by controlling a temperature gradient applied to the grating. A thermodynamic model is presented enabling us to simulate the temperature distribution along the grating lenght. Furthermore, a theoretical approach was de...
Tunable L-band erbium-doped fibre ring laser by means of induced cavity loss us...
M. Melo; O. Frazão; A. L. J. Teixeira; L. A. Gomes; J.R. Ferreira da Rocha; H. M. SalgadoIn this paper, we present a continuous-wave tunable fibre ring laser operating in the L-band. A bi-directional pumped L-band erbium-doped fibre amplifier provides gain to the loop. Tunability is achieved by bending a single-mode fibre taper using a micrometer drive, controlling in this way the spectral cavity losses. Laser emission is achieved between 1587 and 1606 nm, and low variation of the output laser powe...
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