DETECTOR FOR BURGLARY

摘要

PURPOSE:To detect only the application of a high power separately without operating a detector for the small amount of displacement of an optical cable by comprising the detector so as to generate prescribed loss when a prescribed tensile force is applied to the optical cable. CONSTITUTION:The cable is formed by housing an optical fiber 6-1 in a spiral groove 8-1 of cable structure by attaching extra length of 0.05% longer than the minimum length. The cable is mounted in a direction to make the groove 8-1 advance the outside of the radius direction of a mandrel of diameter 35mm mounted at a post between a gap of 2mm via the mandrel. Light of wavelength 1.55mum is made incident on the optical fiber 6-1, and the cable at the intermediate part of the post is displaced by 0-50mm as detecting a receiving light quantity at the other end of the optical fiber. No change occurs in the displacement by 0-35mm of the cable and loss increment due to the micro-bending of the optical fiber 6-1 generated by the displacement of the cable, and increasing tendency for the displacement more than that can be observed.