Distributed optical fiber vibration detection system

The invention discloses a distributed optical fiber vibration detection system. N optical fibers in a detection optical cable are connected in parallel by using a 1 * N optical switch to form N repeatedly arranged detection optical fibers; when a certain point on the optical cable vibrates, through the switching of the optical switch, N points at the same position on the N optical fibers connectedin parallel can be scanned, the vibration can be detected (at the moment, the polarization states of the vibration points of the detection optical fibers are different), and the system gives an alarmas long as a vibration invasion signal is detected at the point on one optical fiber. The probability of polarization fading of one detection point is assumed to be 1%, and when N points detect the point at the same time, the probability of polarization fading is only 0.01 N, so that the probability of missing report is greatly reduced, and the phenomenon of intrusion signal missing detection caused by polarization fading