Department of Electrical Engineering, CEECS, National United University, Miaoli 36063, Taiwan.
Department of Electro-Optical Engineering, National United University, Miaoli 36063, Taiwan.
Sensors (Basel). 2019 Sep 21;19(19):4080. doi: 10.3390/s19194080.
This paper presents a novel measuring scheme for fiber interferometer (FI) based sensors. With the advantages of being small sizes, having high sensitivity, a simple structure, good durability, being easy to integrate fiber optic communication and having immunity to electromagnetic interference (EMI), FI based sensing devices are suitable for monitoring remote system states or variations in physical parameters. However, the sensing mechanism for the interference spectrum shift of FI based sensors requires expensive equipment, such as a broadband light source (BLS) and an optical spectrum analyzer (OSA). This has strongly handicapped their wide application in practice. To solve this problem, we have, for the first time, proposed a smart measuring scheme, in which a commercial laser diode (LD) and a photodetector (PD) are used to detect the equivalent changes of optical power corresponding to the variation in measuring parameters, and a signal processing system is used to analyze the optical power changes and to determine the spectrum shifts. To demonstrate the proposed scheme, a sensing device on polymer microcavity fiber Fizeau interferometer (PMCFFI) is taken as an example for constructing a measuring system capable of long-distance monitoring of the temperature and relative humidity. In this paper, theoretical analysis and fundamental tests have been carried out. Typical results are presented to verify the feasibility and effectiveness of the proposed measuring scheme, smartly converting the interference spectrum shifts of an FI sensing device into the corresponding variations of voltage signals. With many attractive features, e.g., simplicity, low cost, and reliable remote-monitoring, the proposed scheme is very suitable for practical applications.
本文提出了一种新颖的光纤干涉仪（FI）传感器测量方案。光纤干涉仪传感器具有体积小、灵敏度高、结构简单、耐久性好、易于集成光纤通信以及抗电磁干扰（EMI）等优点，适用于监测远程系统状态或物理参数的变化。然而，光纤干涉仪传感器的干涉光谱位移传感机制需要昂贵的设备，如宽带光源（BLS）和光谱分析仪（OSA），这极大地限制了它们在实际中的广泛应用。为了解决这个问题，我们首次提出了一种智能测量方案，其中使用商用激光二极管（LD）和光电探测器（PD）来检测与测量参数变化相对应的光功率等效变化，并用信号处理系统来分析光功率变化并确定光谱位移。为了验证所提出的方案，我们以聚合物微腔光纤菲索干涉仪（PMCFFI）上的传感装置为例，构建了一个能够远距离监测温度和相对湿度的测量系统。本文进行了理论分析和基础测试。给出了典型的结果，验证了所提出的测量方案的可行性和有效性，巧妙地将 FI 传感装置的干涉光谱位移转换为相应的电压信号变化。所提出的方案具有简单、低成本、可靠远程监测等优点，非常适合实际应用。
