Practical Performance Enhancement of DAS by Using Dense Multichannel Signal Integration

Distributed fiber acoustic sensing (DAS) technology can measure acoustic waves along long-distance optical fiber with high spatial resolution. Due to its unique advantages, DAS has been applied in wide fields. However, DAS currently still suffers from limited sensitivity and severe signal fading. Due to the inherent random nature and low signal intensity of Rayleigh backscattering, it is a challenge to essentially eliminate these fundamental limitations. Here a DAS system using its distributed sensing feature is demonstrated with dense multichannel signal integration, complete elimination of signal fading and 100-fold improvement of signal-to-noise ratio (SNR) are experimentally demonstrated. These results provide a simple and effective method to improve DAS performance in practical applications. As far as we know, it is the first time that the distributed sensing characteristic is utilized to tackle fading and sensitivity for DAS, simultaneously. It is believed that this method will promote the process of DAS large-scale applications and help DAS to attract widespread attentions, especially in intrusion detection, acoustic emission flaw detection, near-surface dynamics and characterization, etc.