Optical Fiber Technology ( IF 2.7 ) Pub Date : 2021-07-23 , DOI: 10.1016/j.yofte.2021.102629 Yujia Zhao 1, 2 , Hao Li 2 , Jun Li 2 , Ai Zhou 1, 2
A hybrid cascade structure composed of two Mach–Zehnder interferometers (MZI) is proposed and demonstrated to measure gas pressure and temperature, simultaneously. The key sensing components of the two MZIs are all based on a tapered single mode fiber (TSMF) spliced between two multimode optical fibers. The difference is that one of the TSMFs is covered with PDMS material, while the other one is exposed to air. Because of the large changes in the refractive index versus air pressure and the high thermo-optic coefficient of PDMS, the MZI covered with PDMS has a high sensitivity to gas pressure and temperature. While the MZI exposed to air has only high gas pressure sensitivity because the air is directly involved in the sensing as a signal of interferometer and the effective refractive index of air varies with the pressure. Experimental results show that the gas pressure and temperature sensitivities of the MZI filled with PDMS can be as high as 78.553 nm/MPa and 8.455 nm/°C, respectively, and another MZI can obtain −8.405 nm/MPa and 0.038 nm/°C, respectively. Therefore, the simultaneous measurement can be achieved by utilizing two MZIs with different gas pressure and temperature sensitivities.
中文翻译:
用于同时测量压力和温度的级联光纤 MZI
提出并演示了由两个马赫-曾德干涉仪 (MZI) 组成的混合级联结构,可同时测量气压和温度。两个 MZI 的关键传感组件均基于拼接在两个多模光纤之间的锥形单模光纤 (TSMF)。不同之处在于其中一个 TSMF 覆盖有 PDMS 材料,而另一个则暴露在空气中。由于 PDMS 的折射率随气压变化较大,并且热光系数高,因此覆盖有 PDMS 的 MZI 对气压和温度具有很高的敏感性。而暴露在空气中的 MZI 只有较高的气体压力灵敏度,因为空气作为干涉仪的信号直接参与传感,空气的有效折射率随压力变化。实验结果表明,填充PDMS的MZI的气体压力和温度敏感性分别高达78.553 nm/MPa和8.455 nm/°C,另一种MZI可以达到-8.405 nm/MPa和0.038 nm/°C , 分别。因此,可以通过使用两个具有不同气压和温度敏感性的 MZI 来实现同时测量。