当光纤受到扰动时,通过光纤中的光将发生强度、振幅、或相位等变化。通过检测这种光的变化量可以探测外界的入侵行为。基于马赫-曾德尔干涉原理设计了一种新型干涉式光纤入侵监测系统。通过光纤对入侵者的振动敏感,实现对入侵准确定位。通过差分检测提高了检测灵敏度,从而实现相位变化的解调。该系统结构简单,检测灵敏度高,抗电磁干扰能力强,可以实现远程监测。

When the optical fiber is disturbed, the light through the optical fiber will chang in the light intensity, amplitude, or phase. By detecting the changes, the outside intrusion can be detected. A security-monitoring system based on Mach-Zehnder optical fiber interferometer is introduced in this paper. The optical fiber is sensitive to the intrusion, so the system can determine the position of the intrusion accurately. Differential detection can demodulate this disturbing and can also make system more sensitive. The system is simple, sensitive, strong to electromagnetic interference, and can realize long-distance detecting.