Flooded sensing device and flooding detection method

摘要

PROBLEM TO BE SOLVED: To provide an immersion detection device which can properly detect immersion, even when using an optical fiber having an improved bend loss characteristics (for example, hole-assisted fiber (HAF)), and stably detect immersion under various environments and conditions of immersion detection, and to provide an immersion detection method.;SOLUTION: An immersion detection device 1 comprises an optical fiber 2, an absorption medium 4 which absorbs a fluid and expands, and a stress-imparting portion 3, connected to the absorption medium 4 and having a plurality of projections 5 arranged along a predetermined direction at predetermined intervals. When the absorption medium 4 does not absorb fluid, the projections 5 and the optical fiber 2 are disposed apart from each other so that the predetermined direction is made to coincide with the longitudinal direction of the optical fiber 2. When the absorption medium absorbs fluid and expands, the stress imparting portion 3 forms a long period grating on the optical fiber 2 by the projections 5 by expansion pressure due to the expansion.;COPYRIGHT: (C)2009,JPO&INPIT