A distributed acceleration sensing method using a UWFBG array-based DAS

Acceleration is a key physical quantity in structural health monitoring as it directly reflects the net force acting on a structure. However, conventional acceleration sensing techniques offer only limited spatial coverage. Distributed Acoustic Sensing (DAS) enables vibration measurement along the entire fiber, but acceleration retrieval typically relies on temporal differentiation, which introduces approximation errors and significantly amplifies high-frequency noise. To overcome these limitations, this paper proposes a distributed acceleration sensing method based on a DAS system that employs an ultra-weak fiber Bragg grating (UWFBG) array. The high reflectivity of UWFBGs significantly improves the signal-to-noise ratio (SNR), while three optimized pulse pairs enable interleaved short-time high-frequency sampling. This approach effectively suppresses approximation errors and achieves accurate, high-SNR distributed acceleration measurements.