Ding Xin, Lin Qiao, Liu Shen, Zhang Lianzhen, Chen Nan, Zhang Yuping, Wang Yiping
Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
Guangdong Laboratory of Artificial Intelligence and Digital Economy (SZ), Shenzhen 518107, China.
Sensors (Basel). 2024 Jun 6;24(11):3684. doi: 10.3390/s24113684.
A highly sensitivity balloon-like fiber interferometer based on ethanol coating is presented in this paper. The Mach-Zehnder interferometer is formed by bending a single-mode fiber to a balloon-like structure and nested in the Teflon tube. Then, an ethanol solution was filled into the tube of the balloon-like fiber interferometer by the capillary effect. Due to the high sensitivity of the refractive index (RI) of ethanol solutions to temperature, when the external temperature varies, the optical path difference changes. The change in temperature can be detected by the shift in the interference spectrum. Limited by the size of the balloon-like structure, three kinds of these structures with different sensitive lengths were prepared to select the best parameters. The sensitive lengths were 10, 15 and 20 mm, respectively, and the RI detection performance of each structure in 1026% NaCl solutions was investigated experimentally. The results show that when the sensitive length is 20 mm, the RI sensitivity of the sensor is the highest, which is 212.88 nm/RIU. Ultimately, the sensitive length filled with ethanol is 20 mm. The experimental results show that the temperature sensitivity of the structure is 1.145 nm/°C in the range of 28.1 °C35 °C, which is 10.3 times higher than that of an unfilled balloon-like structure (0.111 nm/°C). The system has the advantages of low cost and easy fabrication, which can potentially be used in high-precision temperature monitoring processes.
本文提出了一种基于乙醇涂层的高灵敏度气球状光纤干涉仪。马赫-曾德尔干涉仪是通过将单模光纤弯曲成气球状结构并嵌套在聚四氟乙烯管中形成的。然后，通过毛细作用将乙醇溶液填充到气球状光纤干涉仪的管中。由于乙醇溶液的折射率（RI）对温度具有高灵敏度，当外部温度变化时，光程差会发生变化。温度变化可通过干涉光谱的移动来检测。受气球状结构尺寸的限制，制备了三种具有不同敏感长度的此类结构以选择最佳参数。敏感长度分别为10、15和20毫米，并对每种结构在10%26% NaCl溶液中的RI检测性能进行了实验研究。结果表明，当敏感长度为20毫米时，传感器的RI灵敏度最高，为212.88 nm/RIU。最终，填充乙醇的敏感长度为20毫米。实验结果表明，该结构在28.1 °C35 °C范围内的温度灵敏度为1.145 nm/°C，比未填充的气球状结构（0.111 nm/°C）高10.3倍。该系统具有成本低、易于制造的优点，可潜在地用于高精度温度监测过程。
