School of Information Engineering, Guangdong University of Technology, Guangzhou 510006, China.
Guangdong Provincial Key Laboratory of Information Photonics Technology, Guangzhou 510006, China.
Sensors (Basel). 2022 Jun 15;22(12):4514. doi: 10.3390/s22124514.
An optical fiber Fabry-Perot interferometer (FPI) is constructed for relative humidity measurement by fusion splicing a short hollow core fiber (HCF) to the end of a single-mode fiber and coating the tip of the HCF with a layer of gelatin. The thickness of the gelatin film changes with ambient humidity level and modulates cavity length of the FPI. Humidity measurement is therefore realized by measuring the wavelength shift of the interreference fringe. RH sensitivity of 0.192 nm/%RH is achieved within a measurement range of 20-80%RH. Dynamic measurement shows a response and recovery time of 240 and 350 ms, respectively. Sensor performance testing shows good repeatability and stability at room temperature but also reveals slight dependence of the RH sensitivity on environmental temperature. Therefore, a fiber Bragg grating is cascaded to the FPI sensing probe to monitor temperature simultaneously with temperature sensitivity of 10 pm/°C.
一种光纤法布里-珀罗干涉仪（FPI）通过将短的空心光纤（HCF）熔接到单模光纤的末端，并在 HCF 的尖端涂覆一层明胶来构建，用于测量相对湿度。明胶膜的厚度随环境湿度水平而变化，并调制 FPI 的腔长。因此，通过测量干涉条纹的波长移动来实现湿度测量。在 20-80%RH 的测量范围内，实现了 0.192nm/%RH 的 RH 灵敏度。动态测量显示响应和恢复时间分别为 240 和 350ms。传感器性能测试表明，在室温下具有良好的重复性和稳定性，但也显示出 RH 灵敏度对环境温度的轻微依赖性。因此，将光纤布拉格光栅级联到 FPI 传感探头中，以同时监测温度，其温度灵敏度为 10pm/°C。
