Distributed fiber-optic dynamic-strain sensor with sub-meter spatial resolution and single-shot measurement

Abstract

A single-shot distributed dynamic strain sensor is proposed with high spatial resolution and broad detection bandwidth. Linear frequency modulated pulse is employed as the probe pulse, which not only solves the trade-off between spatial resolution and sensing distance, but also avoids the time-consuming stepped frequency tuning process. The matrix of Rayleigh backscattering (RBS) at multiple frequencies over the fiber is obtained using the first probe pulse. The strain variation is retrieved from the corresponding frequency shift of the following probe pulses using RBS signature matching. In the demonstrational experiment, distributed vibration measurement with 0.9 m spatial resolution, 224 pϵ/√ Hz strain resolution, 5 kHz response bandwidth and 25.7 dB signal-to-noise radio is realized over 10-km sensing fiber.