Kevin Thomas McCarthy

Temperature-dependent fiber optic hydrogen gas sensor response characteristics

Dynamic response characteristics of silica fiber long-period grating with a modified cladding, composed of ∼10-100 nm nanoparticle palladium oxides thin film material prepared by a magnetron sputtering technique, have been investigated at several elevated temperatures with a 2%H2/98%N2 mixing gas concentration. The fiber cladding modified grating, without cladding chemical etching process, demonstrates 540 pm per 1% H2 sensitivity, a better than 1sec response times at 160oC, respectively. The thermal responses of the prototype have demonstrated increased dynamic wavelength shift while reducing response time simultaneously. The observed thermal dependence of the prototype could be attributed to a combined effect of thermal dependent hydrogen atoms diffusion rate and hydrogen atoms solubility.