Tilted Fiber Bragg Grating Hydrogen Sensor Based On Chemical Plating Method

A tilted fiber Bragg grating(TFBG)hydrogen sensor coated with a palladium(Pd)membrane by the electroless plating method is proposed in this paper.Pd can be used as a sensing element for detecting hydrogen due to its excellent hydrogen absorption ability.Pd forms a uniform membrane on the surface of TFBG through two steps of sensitization and activation(S&A)and electroless plating.Its cauliflower-shaped surface structure has a large surface area and can quickly absorb a large amount of hydrogen.Its cauliflower-shaped membrane surface structure has a large surface area,so a large amount of hydrogen can be absorbed quickly.The absorption of hydrogen by the palladium membrane leads to the unsynchronized change of the Bragg peak and the cladding mode in the transmission spectrum of TFBG,and the cross interference caused by the expansion of the palladium membrane can be eliminated by calculation.Therefore,the device can monitor cracks in the hydrogen transport pipeline while detecting hydrogen gas leakage,and specific detection parameters that vary only for hydrogen concentration can be obtained by calculation.The sensors fabricated herein detected array data within the hydrogen explosion limit(4%)that can quickly respond to a minimum 1% hydrogen concentration signal in 5 minutes.The electroless plating method has the advantages of low cost,simple operation,and can be coated on a long fiber structure.This sensor has been proven to specifically detect hydrogen concentration and to avoid cross-interference caused by temperature changes and fiber micro-deformation by calculation,thus it can be a good candidate for safety applications in the industry.