1. Introduction

Distributed Acoustic Sensing System uses phase sensitive optical time domain reflectometry technology to detect and locate weak vibration events. When the vibration is applied on the sensing fiber/cable, the optical fiber corresponding to the location will vibrate too. Because of the light effect, the refractive index and length of the optical fiber change slightly, which leads to the change of the phase of the transmission signal in the optical fiber. The system uses a highly coherent pulsed light source, so interference occurs between the Rayleigh signals that are scattered back in the pulse-width region. The vibration causes phase change and interference signal intensity change, by changing the strength of Rayleigh scattering light signal detection in different time and position, it detects vibration signal in the optical fiber, and can locate intrusion location events on the sensor cable.

2. Features

>Distance Range up to 40km

>Positioning Accuracy 10m

>Multi point simultaneous alarm

>intelligent identification event type

3. Applications:

>Leakage monitoring

>Thrid-party intrusion monitoring

>Geological fracture monitoring