SUBMERGENCE DETECTION SYSTEM USING SUBMERGENCE DETECTION SENSOR FOR OPTICAL CABLE USING OPTICAL FIBER GRATINGS

摘要

PURPOSE: A submergence detection system is provided to improve the reliability of a measurement and to reduce the system cost by providing an expansive material by flooding and providing optical fiber grating elements in an optical cable. CONSTITUTION: An expansive material(20) is arranged to surround a periphery of an optical fiber(21) so that the expansive material(20) is expanded in a direction parallel with the optical fiber(21) when the material(20) contacted with water. An optical fiber gratings(22) are inserted in the middle of the optical fiber(21) and has an inherent output wavelength. An expansion of the material(20) applies a stress on the optical fiber grating(22) to change signal reference optical characteristics, to thereby detect a submergence with ease.