Hydrogen sensor based on a palladium-coated fibre-taper with improved time-response

We report an experimental study of the response of a hydrogen sensor, based on a palladium-coated tapered optical fibre, at different temperatures in the range −30 to 80 °C. We have studied the transmission, the time-response and the initial response velocity, being able to correlate these measurements with the pressure–composition isotherms of the Pd–H system and its phase transitions. Heating of the palladium layer optically with an auxiliary laser diode permits to improve the sensor's time-response at low temperatures.