Multi-parameter sensor based on the fiber Bragg grating combined with triangular-lattice four-core fiber

摘要

A novel multi-parameter (refractive index, temperature and curvature) sensor based on the splicing-point tapered FBG-SMF-FCF-SMF (FBG, fiber Bragg grating; SMF, single-mode fiber; FCF, four-core fiber) Mach-Zehnder interferometer (MZI) is proposed and fabricated. Two waist-enlarged tapers formed at the fusion points between SMFs and FCF play the roles of the beam splitter and coupler, respectively. FBG is used to monitor temperature change and to compensate for temperature shift in the measurements of refractive index and curvature. The results show that the extinction ratio of transmission spectrum can reach at 27.22 dB. The sensitivities of the sensor to the external refractive index and curvature are 116.396 nm/RIU and 15.57 pm/m(-1), respectively. The temperature sensitivities of MZI and FBG are respectively 67.31 pm/degrees C and 8.73 pm/degrees C in the range of 0-80 degrees C. All the three-parameter measurements present good linear relationship. The sensor has the advantages of simple structure, easy process and low cost, which can be used in multi-parameter detection.