Quasi-distributed fiber sensing via perfect periodic Legendre codes

TL;DR

This paper introduces the use of Perfect Periodic Correlation codes in long-range Quasi-distributed Acoustic Sensing systems, significantly improving sensitivity, bandwidth, and reflected power for long-haul, multi-sensor fiber sensing applications.

Contribution

It demonstrates that selecting optimal code parameters with Perfect Periodic Correlation codes enhances detection bandwidth and reflected power in long-haul Q-DAS systems.

Findings

Order of magnitude increase in detection bandwidth.

Significant improvement in reflected power from sensors.

Enhanced sensitivity in long-range fiber sensing.

Abstract

Long-range Rayleigh-based Distributed Acoustic Sensing (DAS) systems are often limited in their sensitivity and bandwidth. The former limitation is a result of the low backscattered power and poor \textit{dynamic-strain to optical-phase} transduction efficiency. The latter constraint results from the trade-off between range and scan-rate which limits the sampling interval to the longest delay in the sensing fiber. Quasi-DAS (Q-DAS) can yield enhanced sensitivity but may still suffer from low backscattered power and low scan-rate for long-haul, many-sensor, systems. In this work we study the use of Perfect Periodic Correlation codes for interrogating a long-haul Q-DAS system. It is shown that judicious choice of the code parameters allows order of magnitude increase in detection bandwidths and in the power reflected from each sensor.