High sensitivity strain sensor based on a novel offset-core single micro-tapered fiber-optic Mach-Zehnder interferometer

Abstract

A novel offset-core single micro-tapered fiber-optic Mach-Zehnder interferometer (MZI) with high strain sensitivity is proposed and experimentally demonstrated. This novel structure is fabricated only by using ordinary single mode fiber (SMF) and a fiber fusion splicer, of which the offset-core distance is about 12 μm and micro-tapered fiber length is about 490 μm. A high strain sensitivity of −34.61 pm/με is obtained, which is 10 times higher than that (3 pm/με) of common inline optic-fiber MZI and 6 times higher than that (6 pm/με) of common inline optic-fiber Fabry-Perot interferometer (FPI). In addition, the length (∼490 μm) of this novel MZI is much smaller than that of an ordinary inline optic-fiber MZI (∼2 cm) with advantages of high sensitivity, low-cost, and easy fabrication. The novel optic-fiber MZI proposed in this paper enriches the manufacturing methods for fiber-optic MZIs, which has a good application prospect for strain sensing.