Dual parametric simultaneous measurement based on ring-core fiber based MZI cascaded with FBG

Abstract

In the paper, we proposed and experimentally demonstrated a novel sensor for dual parametric simultaneous measurement based on ring-core fiber (RCF)-Mach–Zehnder interferometer (MZI) cascaded with Fiber Bragg grating (FBG). By splicing single mode fibers (SMFs) at both ends of the RCF, two up-taper structures are formed, which act as a beam splitter and a coupler in the MZI, respectively. The experiment proves that the RCF-based MZI has sensitivities of curvature in the range from 0 to 1.71 m⁻¹ and temperature in the range from 30 to 90℃ of this measurement are − 1.25 nm/m⁻¹ and 0.061 nm/℃ while the fitting coefficients are 0.978 and 0.994. The FBG, as a temperature monitor, has no responding to curvature changing, and the temperature sensitivity of 0.0097 nm/℃. The coefficient matrix method is used to measure the curvature and temperature simultaneously, and the problem of temperature cross sensitivity is eliminated. Not only is the sensor capable of simultaneously measuring both curvature and temperature through a straightforward fabrication process, but this sensor has the advantages of high sensitivity, compact structure, low cost and simple fabrication, which makes it have a further application prospect in industrial production.