Distributed optical fiber disturbance sensing system based on phase-sensitive time domain reflectometer (Φ-OTDR) has been a hotspot in intrusion detection. The structure and working principle of Φ-OTDR sensing system were introduced by comparing it with traditional optical time domain reflectometer (OTDR). Based on the development of the Φ-OTDR system, the working principle and research status of four typical Φ-OTDR disturbance sensing systems of traditional, Raman, Brillouin and cascade ones were discussed with the improvement of system structure as the starting point, aiming at improving its sensing distance and location accuracy. Then, their advantages and disadvantages were summarized to provide a direction for selecting the appropriate system in practical application. Finally, the prospect of distributed optical fiber disturbance sensing system based on Φ-OTDR is set forth.
