Improved performance of fiber optic hydrogen sensor based on WO_3-Pd_2Pt-Pt composite film and self-referenced demodulation method

摘要

Optical fiber hydrogen sensor has been a research issue due to its intrinsic safety and anti-electromagnetic interference in recent years. However, its sensitivity and stability still need to be improved to meet the demand of application. Here we present a novel fiber-optic hydrogen platform with significantly enhanced performance, especially for low hydrogen concentrations. The hydrogen sensing system, which consists of two Bragg gratings paired with high-low reflectivities and employs WO_3-Pd_2Pt-Pt composite film as sensing element, can detect hydrogen concentration down 20 ppm in air at ambient temperature of 25 ℃. And the hydrogen sensor exhibits quick response rate and good repeatbility. Moreover, the sensor has good anti-humidity interference and selectivity during hydrogen response. Our work proposes a new concept to develop hydrogen sensing technology with greatly improved performance, which can significantly promote its potential application in various fields.