Optical fiber hydrogen sensor based on evaporated Pt/WO3 film

A reflective fiber optic hydrogen sensor based on evaporated Pt/WO3 film was proposed and experimentally demonstrated in this paper. The optical fiber hydrogen detection system employs a dual-path design of reflective intensity measurement, and therefore to eliminate the noise suffered from light source fluctuation, fiber loss fluctuation, and temperature. The hydrogen sensitive Pt/WO3 film deposited on fused quartz wafer was realized by vacuum thermal evaporation of WO3 and then magnetron sputtering of Pt. The correlation between hydrogen concentration and reflective intensity were investigated and analyzed. Amorphous Pt/WO3 film with porous micro-structure shows good hydrogen sensitive performance. The response value of the proposed sensor increases nonlinearly with hydrogen concentration and the resolution of this type of sensor in low range (0–0.5%) of hydrogen concentration is larger than that in high range (0.5–4%). It provided a simple, economical and effective method to obtain a high sensitivity and good repeatability for detecting a relatively low hydrogen concentration at the room temperature.