Friday, September 21, 2012

Perimeter fence security system using fiber optic cable

As technology evolves so does security and most people may think of additional lighting or adding a security camera system. For those with a high value location you many want to consider perimeter fencing.

Perimeter fencing does involve more then just putting a fence up. Patrolling and other traditional methods with sensors and instruments are often unreliable and expensive. Some systems even have so many false alarms causing distrust in the system.

For a more reliable perimeter fence you may want to employ a AFL fiber optic sensing cable. A fence mounted fiber optic sensing cable for vibration detection and a central sensing device analyzes both the magnitude and pattern of the vibration signatures.

* Responsive: Low false positive rate due to noise generated by environmental factors

* Reliable: High reliability for detection of intrusion events (extremely low frequency of false negitive)

* Accurate: Plus or minus 2.5% accuracy of intrusion event locations over continuous fence line lengths of up to 5 kilometers

* Flexible: Stand alone system of integrated with pan-tilt cameras and other technologies like infrared systems  

This fiber optic system works by using optical power from a laser diode (LD in diagram) is split by the optical coupler and is diffused through an optical fiber ring in two counter directional paths.

When vibration is applied to the fiber, the strength of the interference light fluctuates due to the change in the refractive index in the region of the cable vibration. The emitted light arrives at a vibration point with some difference in time of flight. After passing the vibration point, two counter directional light packets are combined to cause interference. The light interference is detected by a photo diode (PD). Under static conditions (no vibration) the interference light strength is stable.

Here's a quick look at the components of the AFL perimeter fence system.

If this is an option that may work for your location feel free to contact specialist Jeff Jamieson with AFL at 864-486-7115

Questions? Don't hesitate to leave them below.


"By Mercy Salinas"