Distributed Strain Sensing Inside a Fiber Coil under Vibration

This paper investigates the strain distribution in a 1 km fiber coil submitted to a 500 Hz vibration. The strain distribution monitoring system relies on a phase-sensitive optical frequency domain reflectometry exhibiting a 10 kHz refreshing rate and a 40 cm spatial resolution. The phase measurement along the fiber allows retrieving the spatial and temporal distribution of the mechanical strain inside the coil. The system perfectly detects vibrations and mechanical responses of the coil packaging. We also give a qualitative comparison between experimental results and a mechanical simulation of the coil.