Characteristics of hetero-core optical fiber hydrogen sensor based on Au/WO3/Pt thin film

In this paper, we propose a hetero-core optical fiber hydrogen sensor with multilayer gold (Au), tungsten trioxide (WO3), and platinum (Pt) films formed by Radio Frequency (RF) magnetron sputtering technique. We succeeded in detecting hydrogen by using surface plasmon resonance (SPR), which can show a sharp response to the refractive index change of the outside of the fiber. The absorption peak of transmitted spectra in the proposed hydrogen sensor can be adjusted by changing the thickness of the WO3 film. Therefore, it was found that the sensor could have good sensitivity with an infrared LED light source 850 nm wavelength used in practical usage. We also evaluated the measurement reproducibility of the sensor as a hydrogen sensor by evaluating the time response using the LED 850 nm wavelength.