Simultaneous measurement of temperature and curvature using ring-core fiber-based Mach-Zehnder interferometer

In this paper, the Mach-Zehnder interferometer (MZI) based on ring-core fiber was proposed and manufactured. Benefiting from the identical diameters of ring-core fiber, no-core fiber, and single-mode fiber, the MZI fiber sensor can be prototyped by sandwiching the ring-core fiber between the no-core fiber and the single-mode fiber (SMF). With the proposed specific structure of the ring-core fiber, the simultaneous measurement of temperature and curvature was achieved with the MZI sensor by means of monitoring the wavelength shift of interference dips. Experimental results have shown that the sensitivity of curvature sensing could reach up to -3.68 nm/m(-1) in the range from 1.3856 m(-1) to 3.6661 m(-1) with high linearity of 0.9959. Meanwhile, the maximum temperature sensitivity is measured to be 72 pm/degrees C with a fairly good linearity response of 0.9975. In addition, by utilizing the 2x2 matrix algorithm, the dual demodulation of temperature and curvature can be readily realized for the purpose of direct sensing. It is believed that the proposed special structure-based MZI sensor may show great potential applications in the field of fiber-optics sensing and structural health monitoring (SHM). (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

The paper introduces and fabricates a Mach-Zehnder interferometer (MZI) based on ring-core fiber for simultaneous temperature and curvature measurement. The sensor shows high sensitivity and linearity, with the potential for dual demodulation of temperature and curvature using a 2x2 matrix algorithm.