Ultra long distance distributed fiber-optic system for intrusion detection

摘要

This paper research an ultra long distance distributed fiber-optic intrusion detects system. Laser source is amplified and modulated before input to the dual Mach-Zehnder interferometers. This ensures the system can detect longer distance with less loss and nonlinearity than continuous laser input. The cross correlation algorithm is considered to locate the vibration event after the polarization controlled of the optical source, and the locate precision is also discussed. Finally, an experiment result is given as the sensing fiber length is 112km with the location precision about 160m.