The Fiber-optic Sensor for Perimeter Guarding

This paper deals with the practical application of the optical fiber sensors for the specific purpose of intrusion detection systems and the integrity protection of critical infrastructures. Currently, the use of security equipment is primarily based on metallic lines that generally integrate also surveillance cameras, free space detection lasers and other complicated security equipment. This paper shows one of the principles of using glass optical fibers as sensors for dynamic perimeter intrusion detection systems based on perturbation of the optical transmission properties of sensor zone fiber. The bending-pressure perturbations are used to induce optical speckle patterns at the end of sensing multimode fiber. These patterns are further spatially filtered by connected single mode fiber. The use of optical sensor systems has its advantages compared with conventional metallic systems that include stable parameters in time, potential greater guarding coverage due to low attenuation of the zone sensor driving fibers, passive mode of operation without using of active components in a guarded area, and great resistance to electromagnetic interference.