光纤微机电系统法布里-珀罗压力传感器的波分复用

Wavelength Multiplexing of Optical Fiber Microelectromechanical System Fabry-Pérot Pressure Sensors

提出了一种用阵列波导光栅复用光纤微机电系统法布里-珀罗压力传感器的方法，实现了法布里-珀罗压力传感器的准分布式测量。传感器基于法布里-珀罗腔干涉的原理，采用微机电系统技术加工制作，用双波长方法解调干涉信号，利用传感器对两个不同波长光的反射率的比值与压力的单值关系确定所施加压力的大小，用阵列波导光栅实现传感器复用。理论分析与实验验证了传感器解调和复用的基本原理。实验结果表明：在压力的线性测量范围（0～1．5MPa）内，系统的灵敏度（相对反射率比值／压力）可达到0．02026MPa^-1，测量结果具有较好的线形性，相对反射率比值的标准偏差小于3×10^-4.该系统可以补偿传感器光网中和波长无关的变动引起的误差，具有好的线性、灵敏度和精度，复用能力强且复用传感器间无串扰。

In order to realize the quasi-distributed measurement for Fabry-Pérot （F-P） sensors, a multiplexing scheme of optical fiber microelectromechanical system （MEMS） Fabry-Pérot pressure sensors with arrayed waveguide grating is presented. Based on Fabry-Pérot interferometry, the sensors are fabricated with microelectromechanical system techniques and interrogated with the dual-wavelength method. In this method, the single-valued relation between ratio of sensor reflectance at two different wavelengths and the calibrated pressure are used to determine the pressure. The arrayed waveguide grating （AWG） is used to multiplex the sensors. The demodulation and multiplexing principles are theoretically analyzed and experimentally verified. The experimental results demonstrate that in the linear measurement range of pressure （0～ 1. 5 MPa）, the sensitivity （ratio of sensor reflectivity/ pressure） of the system achieves 0. 02026 MPa^-1, the measured ratio has a good linearity with the pressure, and the standard deviation of the reflectance ratio is less than 3 ×10^-4. The system can eliminate errors resulted from wavelength-independent variations in the fiber interconnection to the sensor,and has reasonable linearity, sensitivity and precision. Many sensors can be multiplexed in this system and there is no observable crosstalk among them.