Opt Lett. 2018 Dec 15;43(24):6009-6012. doi: 10.1364/OL.43.006009.
A compact dual-cavity Fabry-Perot interferometer (DC-FPI) sensor is proposed and demonstrated based on a hollow-core photonic bandgap fiber (HC-PBF) spliced with a hollow-core fiber (HCF). The HC-PBF, which has low transmission loss, was used as the first FPI cavity and also acted as a bridge between the lead-in single-mode fiber and the HCF. The HCF was used as the second FPI cavity and also acted as a micro gas inlet into the first FPI cavity. A DC-FPI sensor with different cavity lengths of 226 and 634 μm in the first FPI and the second FPI was created. Both gas pressures ranging from 0-10 MPa and temperatures ranging from 100-800°C were measured using the DC-FPI sensors together with a fast Fourier transform and phase-demodulation algorithm. Experimental results showed that the first FPI cavity was gas pressure sensitive but temperature insensitive, while the second FPI cavity was temperature sensitive but gas pressure insensitive. A high gas pressure sensitivity of 1.336 μm/MPa and a temperature sensitivity of 17 nm/°C were achieved in the DC-FPI sensor. Moreover, the cross sensitivity between the gas pressure and temperature was calculated to be ∼-15 Pa/°C and ∼0.3°C/MPa. The proposed DC-FPI sensors provide a promising candidate for the simultaneous measurement of high pressures and high temperatures at some precise locations.
提出并演示了一种基于熔接有空心光纤（HCF）的空芯光子带隙光纤（HC-PBF）的紧凑型双腔法布里-珀罗干涉仪（DC-FPI）传感器。具有低传输损耗的 HC-PBF 用作第一 FPI 腔，并且还充当了引入单模光纤与 HCF 之间的桥梁。HCF 用作第二 FPI 腔，并且还充当了通向第一 FPI 腔的微型气体入口。创建了具有在第一 FPI 和第二 FPI 中腔长分别为 226μm 和 634μm 的 DC-FPI 传感器。使用 DC-FPI 传感器以及快速傅里叶变换和相位解调算法，测量了从 0-10MPa 的不同气体压力和从 100-800°C 的不同温度。实验结果表明，第一 FPI 腔对气体压力敏感而对温度不敏感，而第二 FPI 腔对温度敏感而对气体压力不敏感。在 DC-FPI 传感器中实现了 1.336μm/MPa 的高气体压力灵敏度和 17nm/°C 的温度灵敏度。此外，计算出气体压力和温度之间的交叉灵敏度约为-15 Pa/°C 和 0.3°C/MPa。所提出的 DC-FPI 传感器为在某些精确位置同时测量高压和高温提供了一种有前途的候选方案。
