基于WO3- Pd复合膜的D型光纤光栅氢气传感器

采用磁控溅射方法在侧边抛磨的光纤光栅（D型光纤光栅）上溅射40 nm WO3-Pd复合薄膜,制作了D型光纤光栅氢气传感器.40 nm WO3-Pd复合薄膜是由5 nm的WO3、5 nm的WO3/Pd混合膜和30 nm的Pd 薄膜组成.实验中,首先采用射频溅射技术向D型光纤光栅溅射5 nm WO3薄膜,再利用共溅射技术溅射5 nm WO3/Pd混合膜,最后用直流溅射技术溅射30 nm的Pd薄膜.SEM结果显示在多次通氢气后WO3-Pd薄膜仍然具有较好的表面形貌,这说明WO3-Pd复合薄膜具有较好的机械性能.实验结果表明:该氢气传感器具有较好的重复性,同镀有同样氢气敏感膜的普通FBG相比,D型光纤光栅的灵敏度提高了200%|在氢气体积浓度为6%时,D型光纤光栅传感器的波长变化为15pm.

Hydrogen Sensor Based on D-shaped Fiber Bragg Grating Coated with WO3-Pd Composite Films

 40 nm WO3-Pd composite film was sputtered on the side-face of side-polished fiber Bragg grating (D-shaped FBG).The FBG sensing head with 40 nm WO3-Pd composite film was firstly prepared by a 5 nm WO3 coating realized with radio frequency（RF）sputtering process,followed by depositing 5 nm WO3/Pd composite film,and then finished with 30 nm Pd film by direct-current(DC) sputtering method.SEM results show that WO3-Pd composite film still has good surface morphology after several cycle′s hydrogen response,which indicates WO3-Pd composite film has good mechnical property.The experiment results demonstrate hydrogen sensor has good repeatability under different concentration hydrogen.Compared to standard FBG coated with same hydrogen sensitive film,the sensitivity of D-shaped FBG is increased by 200%.When the hydrogen concentration is 6% in volume,the wavelength shift of D-shaped FBG is about 15 pm.D-shaped FBG hydrogen sensor has great potential in hydrogen′s measurement.