Single-end-access chaos Brillouin optical correlation domain analysis

Breaking the inherent trade-off between spatial resolution and sensing distance has been a longstanding challenge for single-end-access distributed Brillouin fiber sensors. Here, we propose and experimentally validate a chaotic-laser-based Brillouin optical correlation domain analysis (BOCDA) that enables high-resolution sensing over kilometer-long distances from a single end. To mitigate four-wave mixing interference in long-haul deployment, we introduce an optimized power allocation strategy and a narrowband fiber Bragg grating filter, significantly enhancing spectral purity and signal stability. By leveraging the broadband and noise-like properties of a chaotic laser, we achieve a spatial resolution of 4.0 cm along a 2 km sensing range, yielding over 50,000 effective sensing points. This work demonstrates a practical and high-performance approach to single-end-access Brillouin sensing, opening avenues for large-scale structural health monitoring with centimeter-scale resolution.