基于F-P腔干涉的膜片式光纤微机电系统压力传感器

Diaphragm Type Optical Fiber MEMS Pressure Sensors Based on F-P Cavity Interference

基于法布里-帕罗腔的干涉原理,采用微机电系统技术加工制作了一种光纤微机电系统压力传感器.采用浓硼扩散自停止腐蚀和磁控溅射的方法,制备厚度为6μm、机械灵敏度为0.502μm/MPa的传感器敏感膜.基于强度解调技术,利用干涉腔的反射功率与压力的关系对压力进行解调.分析了腔长变化对反射率的影响,确定传感器线性工作点的波长,建立稳定的压力传感测试系统.测试结果表明,该传感器压强最小分辨率为62Pa,灵敏度达到0.51nW/KPa,具有良好的线性度、灵敏度和重复性,适用于人体内压力测量和口腔义齿压力测量.

A kind of optical fiber MEMS pressure sensor was manufactured by micro electro mechanical systems technology according to the principle of Fabry-Perot cavity interference. A sensitive film which is 6 μm in thickness and 0.502 μm/MPa in mechanical sensitivity was fabricated by adopting the deep boron-diffusion self-stopped etching and magnetron sputtering technique. Based on the intensity-demodulation technology, this kind of pressure sensor makes use of the relation between reflected power and pressure to demodulate the pressure. The study explores the impact of the change of cavity length on reflectance, identifies the light wavelength of linear working point of the pressure sensor, and establishes a stable testing system of fiber Fabry-Perot pressure sensor. The test results show that this kind of sensor has a minimum pressure resolution of 62 Pa and a sensitivity of 0.51 nW/KPa, displaying good linearity, high sensitivity and remarkable repeatability. It can be used to measure the pressure in the human body and the power of the oral denture on the below structure.