Abstract

We present an experimental analysis of the time response of a hydrogen sensor based on a tapered multimode fiber coated with Pd composite thin films. A novel fiber taper coating technique is proposed. The components (Pd and Ag or Pd and Au) are simultaneously deposited over the uniform waist of a tapered fiber at different evaporation rate. Multimode Fiber tapers coated with Pd-Ag and Pd-Au thin films, exposed to 4% hydrogen concentration in pure nitrogen at normal conditions, have shown a time response of 20 and 15 seconds, respectively. The simple detection scheme combined with fast response makes this inexpensive optical fiber hydrogen sensor very attractive.

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