Highly sensitive hydrogen sensor based on a U-shaped microfiber interferometer coated with Pt/WO3

As the extensive application of hydrogen energy, highly sensitive detection of hydrogen is important to prevent the risk of an explosion. To achieve good sensing stability, (3-Aminopropyl) triethoxysilane (APTES) was used to immobilize Pt/WO3 on the U-shaped microfiber sensor. The experimental results show that the proposed U-shaped single mode-tapered four core-single mode (STFS) microfiber sensor has good spectrum stability (maximum wavelength perturbation of 0.013 nm over 30 min) and long-term stability (13 days). Furthermore, when the concentration of hydrogen is changed from 0 % to 1 %, the proposed U-shaped STFS microfiber hydrogen sensor shows a high sensitivity of −17.706 nm/% and a good linearity with a linear regression coefficient of 0.996. The developed hydrogen sensor has temperature and RH sensitivities of 0.0114 nm/℃ and 0.006 nm/%RH, respectively, indicating low temperature and RH cross-sensitivity to hydrogen measurement. The proposed U-shaped STFS microfiber sensor and the functionalized method have potential applications in hydrogen detection, prevention of hydrogen-related accidents and other fields.