基于油封方法的光纤FP温度传感器增敏技术研究

Sensitivity Enhancement Method for Oil-Sealed Fiber Fabry-Perot Temperature Sensor

为了有效提升二氧化硅基底光纤温度传感器的温度灵敏度特性,通过膨胀辅助放电方法形成端部呈微泡结构的光纤Fabry-Perot温度传感器,并对传感器外表面进行镀铬与金膜处理,然后将传感器密封在一个充满硅油的中空圆柱金属体中.由于微泡结构膜层对外界压强比较敏感,所以通过油封方法可有效地将传感器的压强灵敏度特性转化温度增敏效果.实验结果表明,在30~90℃温度变化范围内,油封前后的传感器温度灵敏度分别为6pm/℃和36pm/℃,表明该方法可实现6倍以上的灵敏度增强效果.本文结果对发展新型高灵敏度光纤温度传感器具有一定的参考价值.

In order to improve the sensibility of fiber temperature sensor with silicon dioxide substrate, a novel optical fiber temperature sensor was presented based on the Fabry-Perot （FP） interference of fiber microbubble structure. The improvement is that a silica microbubble with ultrathin film is fabricated and then fused with sin- gle mode fiber by a commerical fusion splicer. And FP interference is formed between the endface of fiber and bubble. Besides, the outside of microbubble is successively coated with Cr film and Au film respectively for iso- lating the outer influence on interference spectrum. Finally, such sensor structure is sealed in a hollow cylinder metal by silicone oil. As the expansion and contraction of silicone oil is related with the outer temperature and easy to influence the deformation of microbubble due to the ultrathin silica film, such sensor structure could be used for temperature t with high sensitivity. Our experiment results show that the peak value of in terference spectrum will shift with the increase of temperature from 30 ℃ to 90 ℃ and its temperature sensitivity is 36pm/℃, which means a six times of sensitivity enhancement is feasible. Besides, the fabrication cost of such sensor is very cheap. The results can supply reference to develop high sensitive fiber temperature sensor.