Ma Chao-Tsung, Chang Yu-Wei, Yang Yuan-Jie, Lee Cheng-Ling
Department of Electrical Engineering, National United University, Miaoli 36003, Taiwan.
Department of Electro-Optical Engineering, National United University, Miaoli 36003, Taiwan.
Sensors (Basel). 2017 Nov 17;17(11):2659. doi: 10.3390/s17112659.
This paper presents a novel design method in which a dual-polymer fiber Fizeau interferometer (DPFFI) is proposed for simultaneously measuring relative humidity (RH) and temperature (T). Since the polymer is intrinsically highly sensitive to both RH and T, the polymer fiber Fizeau interferometer (PFFI) exhibits cross-sensitivity of RH and T. In general, it is difficult to demodulate the optical responses from both variations of RH and T using a single PFFI. If two PFFIs with different structures are combined, they will individually exhibit distinct sensitivity responses with respect to RH and T, respectively. The technical problem of analyzing multiple interferences of the optical spectra of the DPFFI and the individual sensitivity of RH and T to each PFFI is obtained using the fast Fourier transform (FFT). A mathematical method is applied to solve the simultaneous equations of the DPFFI, so that the two variables RH and T can be determined at the same time. Experimental results, indicating good sensitivity and accuracy, with small measurement errors (average errors of ~1.46 °C and ~1.48%, respectively), are shown, determining the feasibility, and verifying the effectiveness, of the proposed DPFFI sensor.
本文提出了一种新颖的设计方法，其中提出了一种双聚合物光纤斐索干涉仪（DPFFI）用于同时测量相对湿度（RH）和温度（T）。由于聚合物本质上对RH和T都高度敏感，聚合物光纤斐索干涉仪（PFFI）表现出RH和T的交叉敏感性。一般来说，使用单个PFFI很难解调来自RH和T变化的光学响应。如果将两个结构不同的PFFI组合在一起，它们将分别对RH和T表现出不同的灵敏度响应。使用快速傅里叶变换（FFT）来解决分析DPFFI光谱的多重干涉以及RH和T对每个PFFI的单独灵敏度的技术问题。应用一种数学方法来求解DPFFI的联立方程，从而可以同时确定两个变量RH和T。实验结果表明，该方法具有良好的灵敏度和准确性，测量误差较小（平均误差分别约为1.46°C和1.48%），确定了所提出的DPFFI传感器的可行性，并验证了其有效性。
