Dual-parameter balloon-type fiber optic sensor based on MIL-101 moisture-sensitive material

Abstract

MIL-101 is a humidity-sensitive metal-organic framework (MOF) material. In this paper, a balloon-type optical fiber sensor based on the metal-organic framework is proposed, which uses a hybrid structure of fiber Bragg grating (FBG) and balloon-type curved optical fiber, and the humidity-sensitive material (MIL-101) is coated near the geometric center of the balloon-type optical fiber to form a laminated film (LF) structure. When the material absorbs water molecules, its refractive index changes, thus realizing the humidity sensitivity and sensing the temperature using FBG. Based on the above sensing mechanism, the structure realizes the dual parameter detection of temperature and relative humidity. The experimental results show that the fiber optic sensor has a relative humidity sensitivity of 221.6 pm/%RH and a temperature sensitivity of -74.58 pm/℃. This composite structure fiber optic sensor combined with new materials provides good technical conditions for achieving the measurement of ambient temperature and relative humidity.