Enhancement for Φ-OTDR performance by using narrow linewidth light source and signal processing

Meng Zhang,Xingjie Sa,Li Zhang,Song Wang,Yuanwei Zheng,Yao Yang

doi:10.1007/s13320-015-0283-7

Abstract

In order to enhance the signal-to-noise-ratio of a distributed acoustic sensing system based on phase-sensitive optical time-domain reflectometry (Φ-OTDR), we have proposed a combination of segmented unwrapping algorithm, averaging estimation of phase difference, and infinite impulse response (IIR) filtering method. The enhancement of signal quality is numerically demonstrated. Moreover, we have studied the influence resulted from the light source noise on the Φ-OTDR performance. The result has shown that when the linewidth of light source used in the Φ-OTDR system is narrower, the performance of the system is better. In a word, such a Φ-OTDR system could obtain higher quality demodulated signals when the narrower linewidth light source is chosen and the method of averaging estimation phase difference is used.

Highlights

Phase-sensitive optical time-domain reflectometry (Φ-OTDR) is a powerful technique that allows fully distributed vibration sensing with fast response and high sensitivity
In order to improve the performance of I/Q phase demodulation of the Φ-OTDR, we have proposed the combination of segmented unwrapping algorithm, averaging estimation of phase difference, and infinite impulse response (IIR) filtering method
We have studied the influence on the Φ-OTDR by introducing light source noise with zero mean and different variance

Summary

Introduction

Phase-sensitive optical time-domain reflectometry (Φ-OTDR) is a powerful technique that allows fully distributed vibration sensing with fast response and high sensitivity. It has been applied in many fields such as civil structure health monitoring and security guarding [1, 2]. Acquiring vibration location has been achieved in the reported Φ-OTDR system by monitoring the amplitude change of backscattered light [3,4,5]. In order to improve the performance of I/Q phase demodulation of the Φ-OTDR, we have proposed the combination of segmented unwrapping algorithm, averaging estimation of phase difference, and infinite impulse response (IIR) filtering method. We have studied the influence on the Φ-OTDR by introducing light source noise with zero mean and different variance

Schematic setup

Conclusions