With the distributed vibration monitoring system from FOS&S, available from Applied Measurement Australia , a single optical fibre is used to serve as a distributed vibration detector. The total length of the sensing fibre can be up to 40 km and the spatial resolution of the measurement is 10 m. This means that the entire fiber should be regarded as being composed of point-like sensors, located at 10 m from each other over a total length of up to 40 km i.e. 4000 sensing points.
The operating principle of the distribution vibration monitoring system is based on pulsed interferometric interrogation and this way of detection is extremely sensitive. It is even sensitive enough to allow the detection of minute pressure variations originating from acoustic vibrations that occur in the vicinity of the sensing fibre. This way, the vibration monitoring system can register acoustic signals generated by e.g. passing cars, walking people, earth works and so on and hence it opens up many opportunities for demanding, long distance security and surveillance applications such as pipeline monitoring, border control, perimeter surveillance and many more.