Objective Aiming at the problem of the narrow dynamic range of current optical fiber displacement sensors, a balloon-like long-period fiber grating (LPFG) displacement sensor with a simple structure and easy preparation method is designed.

Methods Based on simulation and optimization by RSOFT software, the measurement range is determined by the balloon-like optical fiber under different curvatures. A multimode fiber balloon-like LPFG (MMF-BLPFG) formed by periodically embedding multimode fiber (MMF) into single-mode fiber (SMF) provides a reference peak for measuring the displacement. Using a precise continuous cutting device as the experimental basis, test samples consistent with the simulation results are prepared for testing.

Results The maximum displacement measurement range of 36 mm is achieved by measuring the drift of two resonance peaks.

Conclusions The proposed sensor has good application potential in large-scale measurement scenarios such as the stability measurement and continuous monitoring of the underwater drainage space piping systems of ships.