SnO2-MOF-Fabry-Perot optical sensor for relative humidity measurements

Abstract

In this paper, a new optical fiber sensor for relative humidity measurements is presented and characterized. The sensor is based on a SnO2 sputtering deposition on a microstructured optical fiber (MOF) low-finesse Fabry-Pérot (FP) sensing head. The feasibility of the device as a breathing sensor is also experimentally demonstrated. The interrogation of the sensing head is carried out by monitoring the Fast Fourier Transform phase variations of the FP interference frequency. This method substitutes the necessity of tracking the optical spectrum peaks or valleys, which can be a handicap when

Real Time Measuring System of Multiple Chemical Parameters Using Microstructured Optical Fibers Based Sensors

“…In this work, the deposition time of each sensor has been selected in order to enable simultaneous measurement in the same atmosphere avoiding crosstalk between sensors. For this reason, their sensitivity is not maximal when compared with the results showed in [46], [55], [56], as they were optimized.…”

“…Relative humidity sensors were developed by creating a thin film of SnO2 inside the holes of the MOF fiber through the sputtering process, as authors previously demonstrated in [55]. VOCs presence sensors were developed with the same technique but changing the sensing material to ITO [56].…”

Comparison between Capacitive and Microstructured Optical Fiber Soil Moisture Sensors

“…Microstructured optical fibers (MOFs) present great sensing potential and they have shown improved properties over traditional optical fiber sensors overcoming some of their handicaps [14][15][16]. For example, several pure silica suspended-core fibers have been used in temperature and curvature sensing [17], gas sensing [18], or relative humidity (RH) sensing [19].…”

“…In this work, an optical fiber sensor based on a sputtering deposition on a MOF is presented for real moisture measurements and compared simultaneously with a commercial capacitive sensor. The operation principle of the humidity optical sensor has been previously reported by authors [19] showing in detail the construction process of an optimized sensing head and its performance towards humidity variations. In the present paper, the authors propose, for the first time, a sensor that has been adapted and used for measurements in real soil conditions.…”

“…Moreover, the authors also present a comparison between the performance of microstructured optical fiber sensors, a commercial capacitive sensor, and a comparison of both devices against gravimetric measurements, showing the pros and cons of every type of sensors (and remarking the advantages of fiber optic against commercial capacitive ones). It is worth remarking that the aim of this work is not to present the optical sensing head in detail, as it is fully described in [19], but to show a real comparison between commercial capacitive soil moisture sensors and the application of the optical sensing head for the same purpose.…”