Tapered-open-cavity-based in-line Mach-Zehnder interferometer for highly sensitive axial-strain measurement

An in-line Mach-Zehnder interferometer based on a multimode-fiber-assisted tapered open-cavity (TOC) is proposed. Light field distributions of the TOC were investigated using beam propagation method with different offsets and diameters of the taper waist. Bias and uniform taper (BT and UT)-based structures were fabricated and compared using one- and two-step arc-discharge methods, and comprehensive tests were then conducted considering axial-strain. The experimental results show that the UT structure has more than -45 pm/mu epsilon linear wavelength shift with the applied axial-strain. Owing to its compact size and low cost, the proposed sensor is promising for axial-strain-related high-precision engineering applications. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

This study proposes an in-line Mach-Zehnder interferometer based on a multimode-fiber-assisted tapered open-cavity (TOC). Experimental results show that the interferometer has a linear wavelength shift of over -45 pm/mu epsilon with applied axial-strain. Due to its compact size and low cost, the sensor is promising for high-precision engineering applications related to axial-strain.