Huang Wei, Zhang Zhe, He Jun, Du Bin, Liao Changrui, Liu Shen, Yin Guolu, Wang Yiping
Guangdong and Hong Kong Joint Research Centre for Optical Fibre Sensors, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
Guangdong Laboratory of Artificial Intelligence and Digital Economy (SZ), Shenzhen University, Shenzhen 518060, China.
Sensors (Basel). 2020 Apr 30;20(9):2548. doi: 10.3390/s20092548.
We demonstrate a silica diaphragm-based fiber tip Fabry-Perot interferometer (FPI) for high-pressure (40 MPa) sensing. By using a fiber tip polishing technique, the thickness of the silica diaphragm could be precisely controlled and the pressure sensitivity of the fabricated FPI sensor was enhanced significantly by reducing the diaphragm thickness; however, the relationship between the pressure sensitivity and diaphragm thickness is not linear. A high sensitivity of -1.436 nm/MPa and a linearity of 0.99124 in hydraulic pressure range of 0 to 40 MPa were demonstrated for a sensor with a diaphragm thickness of 4.63 μm. The achieved sensitivity was about one order of magnitude higher than the previous results reported on similar fiber tip FPI sensors in the same pressure measurement range. Sensors with a thinner silica diaphragm (i.e., 4.01 and 2.09 μm) rendered further increased hydraulic pressure sensitivity, but yield a significant nonlinear response. Two geometric models and a finite element method (FEM) were carried out to explain the nonlinear response. The simulation results indicated the formation of cambered internal silica surface during the arc discharge process in the fiber tip FPI sensor fabrication.
我们展示了一种基于二氧化硅膜片的光纤尖端法布里 - 珀罗干涉仪（FPI）用于高压（40 MPa）传感。通过使用光纤尖端抛光技术，可以精确控制二氧化硅膜片的厚度，并且通过减小膜片厚度显著提高了所制备的FPI传感器的压力灵敏度；然而，压力灵敏度与膜片厚度之间的关系不是线性的。对于膜片厚度为4.63μm的传感器，在0至40 MPa的液压范围内展示出了-1.436 nm/MPa的高灵敏度和0.99124的线性度。所实现的灵敏度比在相同压力测量范围内报道的类似光纤尖端FPI传感器的先前结果高约一个数量级。具有更薄二氧化硅膜片（即4.01和2.09μm）的传感器具有进一步提高的液压灵敏度，但产生明显的非线性响应。进行了两种几何模型和有限元方法（FEM）来解释非线性响应。模拟结果表明在光纤尖端FPI传感器制造过程中的电弧放电过程中形成了弯曲的内部二氧化硅表面。
