Liquid Seal for Temperature Sensing with Fiber-Optic Refractometers

Sensors

Ben Xu²  Jianqing Li²  Yi Li¹  Jianglei Xie¹ 

[1] College of Optical and Electronic Technology, China Jiliang University, Hangzhou 310018, China; E-Mails:;Faculty of Information Technology, Macau University of Science and Technology, Macao, China; E-Mail:

关键词: fiber-optic refractometer;    temperature sensor;    liquid seal;    thermo-optic effect;   

DOI  :  10.3390/s140814873

来源: mdpi

【 摘 要 】

Liquid sealing is an effective method to convert a fiber-optic refractometer into a simple and highly sensitive temperature sensor. A refractometer based on the thin-core fiber modal interferometer is sealed in a capillary tube filled with Cargille oil. Due to the thermo-optic effect of the sealing liquid, the high refractive-index sensitivity refractometer is subsequently sensitive to the ambient temperature. It is found that the liquid-sealed sensor produces a highest sensitivity of −2.30 nm/°C, which is over 250 times higher than its intrinsic sensitivity before sealing and significantly higher than that of a grating-based fiber sensors. The sensing mechanisms, including the incidental temperature-induced strain effect, are analyzed in detail both theoretically and experimentally. The liquid sealing technique is easy and low cost, and makes the sensor robust and insensitive to the surrounding refractive index. It can be applied to other fiber-optic refractometers for temperature sensing.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.