FIBRE-OPTIC INTRUDER ALARM SYSTEM

摘要

To enhance the sensitivity and certainty of detecting an intruder, a fibre-optic alarm system is provided with a fibre-optic coupler (7) and a reflector (11), the output of the coherent radiation source (1) being connected to the first port (8) of a fibre-optic coupler (7) whose second port (9) is connected to the first output of a multimode optical waveguide (2) whose second output is connected to the mirror of the reflector (11), while the third port (10) is connected to the input of the photodetector (3).