Optical fiber strain and temperature sensor based on an in-line Mach–Zehnder interferometer using thin-core fiber

Abstract

We propose and demonstrate a fiber in-line Mach–Zehnder interferometer using thin-core fibers. This in-line interferometer is composed of a short section of thin-core fiber inserted between two single mode fibers (SMF), and demonstrated as a strain and temperature sensor in this study. A strain sensitivity of −1.83pm/με with a measurement range of 0−2000με, and the temperature sensitivity of −72.89pm/°C with a temperature variation of 50°C are achieved. We also discussed that the influence of strain and temperature change on the relative power ratios among the excited cladding modes in thin-core fibers.