一种新型微结构高灵敏度光纤温度传感器

A new type of high sensitivity optical fiber temperature sensor with microstructure

为实现高精度温度检测,提出一种基于飞秒激光微加工的新型光纤温度传感器的制备方法。利用波长为780nm的飞秒激光脉冲在刻写有光纤布拉格光栅(FBG)的单模光纤(SMF)包层上加工槽状微结构,通过磁控溅射的方法在其表面沉积温敏薄膜,从而制备一种光纤温度传感探头。理论分析了环状微结构镀膜实现温度增敏的工作机制,通过温度实验讨论了不同微结构镀膜对温度增敏效果的影响。实验结果表明,在FBG包层上单纯加工槽状微结构(无镀膜),对温度的灵敏度影响不大,基本上不改变光栅中心波长随温度变化的趋势;加工槽状微结构后再沉积敏感薄膜,可明显提升传感器的温度灵敏度,其中环状膜层较镀膜螺纹膜层微结构的增敏效果更加明显,其灵敏度可达21.37pm/℃。

To realize the high-precision temperature detection,a new type of fiber optic temperature sensor is proposed based on femtosecond laser micromachining. The femtosecond laser with wavelength of 780nm is employed to ablate a groove-shaped microstructure into the cladding of single mode fiber with Bragg grating （FBG）. By magnetron sputtering process, a sensitive film （TbDyFe） is deposited on the mierostrueture to make a new fiber optic temperature sensor probe. To the coated annular microstructure,the mechanism of enhancing sensitivity to temperature is analyzed. The effects of different microstructures on temperature sensitivity are discussed. The experimental results show that the groove shaped rnicrostructure without coating has almost the same sensitivity with the normal FBG,and it also couldn＇t change the trends of the center wavelength with the temperature. However, as the sensitive film is deposited on the FBG cladding with groove-shaped microstrueture,its sensitivity can be improved significantly. Moreover, the annular microstructure has better sensitization effect than the screw thread microstructure,and the temperature sensitivity can reach 21.37 pro/℃.