Long-distance fiber-optic Φ-OTDR intrusion sensing system

Abstract

A novel fiber-optic phase-sensitive optical time-domain reflectometer (Φ-OTDR) distributed sensing system is proposed and demonstrated for long-distance intrusion monitoring. By using the bi-directional Raman optical amplification technology, even intrusion signal detection along the whole sensing distance of ~62km has been demonstrated, resulting in the longest and the most sensitive Φ -OTDR distributed sensing system reported so far, to the best of our knowledge. In addition, high-power single-mode fiber laser with ultra-narrow line-width and special optical fiber cable encapsulated by fiber reinforced plastic (FRP) are used to further enhance the intrusion detection sensitivity, respectively.