Fiber optics based intrusion detection system

Abstract

This research is aimed at development of fence mounted or buried optical fibre based intrusion detection system. Type and location of intrusion will be determined based on the principle of interferometry using counter propagating optical signals in the fibre. The system employs Mach-Zehnder interferometer through which counter propagated signals are launched. If there is some intrusion anywhere in the entire length of fibre the counter propagated signals are modified. The modified signals are detected on a photo detector. The type of intrusion i.e., touching, cutting, stepping over a fibre can be identified on the basis of modified signals. Time difference between receipts of modified counter propagated signals is used to determine the location of the event.