Low-noise Brillouin random-access dynamic sensor based on chirped pulse

Dynamic sensing and high-accuracy measurement constitute two core technical bottlenecks in conventional Brillouin optical time-domain analysis (BOTDA) sensors, which inherently involve a mutually restrictive trade-off rooted in their operational principles. This study presents an ultra-low-noise Brillouin random-access dynamic sensor based on a chirped pulse. By leveraging random-access functionality and single-shot measurement capability, the sensor realizes a dynamic single-end BOTDA configuration where performance is solely constrained by the pulse time-of-flight. Ultra-low-noise detection is achieved by removing modulator timing jitter, optimizing the chirp rate, and reducing laser phase noise, and using cross-correlation demodulation to mitigate uncertainties arising from transient waveform distortions. Consequently, the sensor delivers an average strain resolution of 3.42 nε/Hz (with a minimum of 2.66 nε/Hz), a sensor bandwidth of 25 kHz, and a spatial resolution of 10 m over a 1 km polarization-maintaining fiber. To date, it represents one of the most accurate Brillouin dynamic sensors reported in the literature, offering substantial application potential in critical fields such as civil structural health monitoring and oil/gas pipeline leakage detection.