Pushing the Reach of Fiber Distributed Acoustic Sensing to 125 km Without the Use of Amplification

Abstract

We report the longest reach fiber based distributed acoustic sensor (DAS) without inline amplification. A measurement range exceeding 112 km, and 125 km if the far end is optimized, is realized with a suitable signal to noise ratio (SNR) for real-world applications. This is achieved by a DAS system optimized for long distance measurements and a combination of different fiber types optimized either for low loss or for high backscatter coefficient.