Research on fiber-optic torsion sensor based on air-gap-embedded waveguide Mach-Zehnder interferometer
SHI Cong
PANG Qingshun
ZHANG Liqiang
YAO Yicun
Abstract：Cladding waveguide Mach-Zehnder interferometers(MZIs)exhibit advantages such as well-de-fined spectral characteristics and high sensitivity,making them suitable for various fiber-optic sensor con-figurations.In this work,femtosecond laser micromachining technology was employed to directly inscribe optical waveguides within standard single-mode fibers,constructing an inline cladding waveguide MZI.By intentionally introducing air gaps within the waveguide structure,the contrast of the interference spectrum was significantly enhanced.During torsion experiments,the sensor demonstrated intensity and wavelength sensitivities of up to-1.007 dB/(rad·m-1)and 1.478 nm/(rad·m-1),respectively,within the range of-13.08 rad/m to 13.08 rad/m.Compared with conventional structures,the incorporation of air gaps not only improved the torsion response sensitivity but also achieved compensation for axial strain,resul-ting in reduced cross-sensitivity.This configuration shows promising potential for high-sensitivity fiber-optic torsion sensing applications in fields such as structural health monitoring and biomimetic robotics.
Keywords：femtosecond laser micromachiningMach-Zehnder interferometerfiber-optic torsion sensing
Publication Date：2025-12-31
Online Publishing Date：2026-08-28(First online date of this platform, not the publication date of the document)
Pages：8( 874-881 )