Nano-structured Pd-long period fiber gratings integrated optical sensor for hydrogen detection

Xiaotong Wei, Tao Wei, Hai Xiao, Jerry Lin

Research output: Contribution to journalArticlepeer-review

88 Scopus citations


A fiber-optic sensor for detecting hydrogen at various temperatures (30-200 °C) is reported in this paper. The sensor is composed of a long period fiber gratings coated with a nano-structured Pd thin layer as the sensing material. The sensing principle of the designed sensor is based on the change of the refractive index of the Pd thin layer upon exposure to hydrogen, which causes the resonance wavelength shift of the long period fiber gratings. The Pd layer prepared by sputter deposition has nanograins of 30-40 nm in size. The resonance wavelength of the long period fiber gratings coated with Pd decreases as hydrogen concentration increases from 0% to 16% at all temperatures. There is a significant wavelength shift of the sensor when the Pd film goes through the phase transition between α and β phases. The sensor has a short response time with a relatively slower recovery rate. The sensor maintains its functionality after several cycles of hydrogen detection and recovery.

Original languageEnglish (US)
Pages (from-to)687-693
Number of pages7
JournalSensors and Actuators, B: Chemical
Issue number2
StatePublished - Sep 25 2008


  • Hydrogen sensor
  • Long period fiber gratings
  • Pd
  • Response time
  • Stability

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry


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