Open AccessChannel-multiplexing for quasi-distributed acoustic sensing with orthogonal codes
Author(s) -
Jialin Jiang,
Ziwen Deng,
Zinan Wang
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.440269
Subject(s) - multiplexing , computer science , hydrophone , bandwidth (computing) , distributed acoustic sensing , frequency domain , electronic engineering , channel (broadcasting) , acoustics , telecommunications , optics , optical fiber , fiber optic sensor , physics , engineering , computer vision
With the increasing demands for large-scale acoustic sensing in many important fields such as hydrophone, vehicle tracking and pipeline monitoring, optical fiber-based distributed acoustic sensing (DAS) has experienced a rapid development. In recent years, quasi-distributed acoustic sensing (QDAS) based on single mode fiber with enhanced point array has emerged, which is a good approach to improve signal-to-noise ratio and deal with the interference-fading problem in DAS. However, similar to DAS, the performance of QDAS is also limited by the finite frequency domain resources. To break the trade-off between sensing bandwidth and distance, additional frequency domain resources are always needed to multiplex the sensing channel. Multiple-input multiple-output coding technology is an approach to realize QDAS channel-multiplexing with the orthogonal probe waves in the same frequency band. In this paper, the iteration constrain condition of the orthogonal codes is modified, and the generation method of more orthogonal codes with high and consistent suppression ratio for QDAS is provided. In the demonstration experiment, the QDAS has successfully achieved 5 times the sensing bandwidth expansion on a 5.19 km fiber based on 5 new orthogonal codes on the same frequency, with 5 m spatial resolution and 10 p ε / H z strain noise level.