Microstructured FBG hydrogen sensor based on Pt-loaded WO.

Hydrogen gas sensing properties of Pt-WO films on spiral microstructured fiber Bragg grating (FBG) has been demonstrated. Pt-WO film was prepared by hydrothermal method. The spiral microsturctured FBG was fabricated using femtosecond laser. Spiral microstructure FBG hydrogen sensor can detect hydrogen concentration from 0.02% H to 4% H at room temperature, and the response time is shortened from a few minutes to 10~30 s. Double spiral microstructure at pitch 60 μm and sputtered with 2 μm Pt-WO film recorded hydrogen sensitivity of 522 pm/%(v/v) H responding to hydrogen gas in air. This translated to approximately 2~4 times higher than the unprocessed standard FBG. The humidity has little effect on the sensing property. The sensor has fast response time, good stability, large detection range and has the good prospect of practical application for hydrogen leak detection.