title: Liquid seal for temperature sensing with fiber-optic refractometers.
abstract: 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.
authors.affiliation: Faculty of Information Technology, Macau University of Science and Technology, Macao, China. xubenfiles@163.com.
authors.forename: Ben
authors.initials: B
authors.lastname: Xu
authors.affiliation: Faculty of Information Technology, Macau University of Science and Technology, Macao, China. jqli@must.edu.mo.
authors.forename: Jianqing
authors.initials: J
authors.lastname: Li
authors.affiliation: College of Optical and Electronic Technology, China Jiliang University, Hangzhou 310018, China. yli@cjlu.edu.cn.
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Optical and Electronic Technology, China Jiliang University, Hangzhou 310018, China. 1208030014@cjlu.edu.cn.
authors.forename: Jianglei
authors.initials: J
authors.lastname: Xie
authors.affiliation: College of Optical and Electronic Technology, China Jiliang University, Hangzhou 310018, China. xydong@cjlu.edu.cn.
authors.forename: Xinyong
authors.initials: X
authors.lastname: Dong
mesh_terms: D004867:Equipment Design / Q000379:methods; D005336:Fiber Optic Technology / Q000379:methods*; D055100:Optical Fibers; D055095:Optics and Photonics / Q000379:methods; D012031:Refractometry / Q000379:methods*; D013696:Temperature