INTRUSION DETECTOR

摘要

PROBLEM TO BE SOLVED: To highly accurately detect an intrusion action at a low cost. SOLUTION: When the intrusion action of shifting the position of the wire of a fence 10 for stipulating a monitoring area 3 or the like is performed, external force by the intrusion action is transmitted to an optical fiber 4 and polarization fluctuation by the change of refractive index is generated in light emitted from a light source 2 and propagated inside the optical fiber 4. The polarization fluctuation is detected in a polarization fluctuation detector 6 and an alarm is outputted from an intrusion judgement device 8 based on detection signals S6.