报道了一种基于飞秒激光加工的微纳高温振动传感器。通过熔接形成单模光纤-空芯光纤-单模光纤的结构, 利用单模光纤和空芯光纤在熔接面形成的菲涅尔反射, 构成外腔式法布里-珀罗干涉仪(EFPI)。用飞秒激光烧蚀空芯光纤, 形成悬臂梁结构。末端的单模光纤作为质量块, 在受到振动时带动悬臂梁振动, 使悬臂梁产生微弯, 进而使EFPI腔长发生变化。实验结果表明, 传感器的工作区域为20~300Hz, 在100Hz时, 0~3.01g范围内测得加速度分辨率为5×10-4g, 加速度响应灵敏度为129.6nm/g。传感器受温度影响小, 腔长的温度交叉响应仅为0.225nm/℃, 传感器可耐950℃高温冲击。

A micro vibration sensor fabricated by femtosecond laser for high-temperature applications is demonstrated. The sensor is based on the configuration of an extrinsic Fabry-Perot interferometer (EFPI), which is formed by a hollow core fiber (HCF) sandwiched between two sections of single mode fiber (SMF). Part of the HCF is removed by a femtosecond laser and a cantilever beam is obtained. A section of the SMF acting as the mass block can oscillate vertically when the sensor is subject to vibration. Within the frequency range of 20-300Hz, the experimental results show that the sensitivity of 129.6nm/g@100Hz is achieved in the acceleration range from 0 to 3.01g. The temperature response of the EFPI cavity is 0.225nm/℃. The sensor can operate stably at a high temperature of 950℃.