Gasoline quality sensor based on tilted fiber Bragg gratings

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOWe report on the study of an intensity-based optical fiber sensor for gasoline quality monitoring. The sensor setup employs two Bragg gratings with different spectral responses to interrogate the optical response of a tilted Bragg grating. The sensor operation is based on the tilted Bragg grating sensitivity to external refractive index changes, which are translated as power variations by the interrogation scheme. Gasoline-ethanol solutions with concentrations ranging from 0% to 60% ethanol were used to demonstrate the sensor performance. The results allowed to estimate that the sensor is able, within its resolution limit, to detect ethanol concentration variations of 1.5% in gasoline-ethanol solutions and discriminate temperature variations of 0.5 degrees C. The all-optical sensor setup is compact and robust, making it a competitive alternative for the realization of fuel quality analyses in practical applications.6218FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO2014/50632-6Sem informaçã

Method of measuring monochromatic light wavelength by using wavelengthsensitiveoptical components

U ovoj doktorskoj disertaciji dat je predlog nove metode za merenje talasne dužine monohromatske svetlosti pomoću spektralno osetljivih optičkih komponenti. Princip rada predložene metode se zasniva na kombinovanju spektralnih osetljivosti fiber-optičke račve i dva različita fotodetektora. Izvršena je implementacija i karakterizacija senzorskog sistema za merenje talasne dužine monohromatske svetlosti. U eksperimentalnoj postavci korišćena je 2×2 fiber-optička račva, germanijumska (Ge) fotodioda i indijum-galijum-arsenid (InGaAs) fotodioda. Postignuta je linearnost sa faktorom korelacije R2=0.99942 i merna rezolucija od 17 pm u opsegu talasnih dužina svetlosti od 1575 do 1615 nm (L-opseg). U istom opsegu, dobijena je merna greška od približno ±0.2 nm i ponovljivost od ±0.16 nm. Ispitani su uticaji promena temperature, snage optičkog izvora i šuma na karakteristike senzorskog sistema.In this thesis, a new method for measurement of monohromatic light wavelength by using wavelength-dependent optical components is proposed. The principle of operation of the proposed method is based on combining spectral sensitivities of fiber-optic coupler and two different photodetectors. Sensor system for measurement of monochromatic light wavelength is implemented and characterized. Experimental setup consists of 2×2 fiberoptic coupler, germanium (Ge) photodiode and indium-gallium-arsenide (InGaAs) photodiode. Excellent linearity (R2=0.99942) and measurement resolution of 17 pm are achieved in measurement range 1575-1615 nm (Lband). In the same measurement range, measurement error of approximately ±0.2 nm and repeatibility of ±0.16 nm are obtained. The influence of temperature, optical source power and noise on sensor system characteristics is investigated