Fading noise reduction in distributed acoustic sensing using an optimal weighted average algorithm

To the best of our knowledge, we present what we believe is a novel approach for fading noise reduction in distributed acoustic sensing (DAS). Rayleigh signals in multiple optical modes are collected by a phase-sensitive optical time-domain reflectometry system with a diversity detection scheme. An optimal weighted average algorithm is proposed to synthesize the phase demodulated from the Rayleigh signals, leading to the aggregate phase that presents acoustic signals with optimal fading noise reduction. The validity of the proposed approach is experimentally confirmed by comparison of the fading noise along a 12.8 km sensing fiber in a conventional DAS system and a DAS system that employs the proposed approach.