(IEEE, 2019) López Torres, Diego; López Aldaba, Aitor; Elosúa Aguado, César; Auguste, Jean-Louis; Jamier, Raphael; Roy, Philippe; López-Amo Sáinz, Manuel; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
In this paper, the influence of the thickness of
metallic-oxide coatings, ITO, and SnO2 on the sensitivity of a
microstructured optical fiber Fabry–Pérot (FP) has been studied
with the aim of developing ammonia gas fiber optic sensors.
Also, the distribution of the optical power that can be coupled
to the metallic-oxide sensing films is investigated in order to
understand how the sensor’s sensitivity can be improved; the
thickness of the coatings plays a relevant role on the sensitivity
and response time. Films with thicknesses between 200 and
850 nm were experimentally examined resulting in an optimal
thickness of 625 nm for a SnO2 film. The behavior of the sensors
toward different concentrations of ammonia gas from 10 to
130 ppm was analyzed by measuring the phase shifts of the
reflected signal using the fast Fourier transform of its optical
spectrum. The registered response/recovery times of this sensor
are below 90 s.
