Device for measuring bent shape of optical fiber and method for measuring bent shape thereof

摘要

PROBLEM TO BE SOLVED: To provide an optical fiber bent shape measurement device and method with which it is possible to perform long distance measurement and seamless distribution measurement in a bend shape sensor technique using an optical fiber.SOLUTION: The optical fiber bent shape measurement device comprises: a Brillouin analyzer 20 for directing the same pump light and the same probe lights into cores C1-C4 of an optical fiber sensor head; and optical receivers 21-24 for measuring, for each of the cores C1-C4, the longitudinal distribution of Brillouin frequency shift amounts in the optical fiber sensor head, finding the strain amounts ε1-ε4 of the cores C1-C4 at each point from the Brillouin frequency shift amounts of the cores C1-C4 at each point, analyzing an angle θ formed by a line linking the center of bend C and the center of cross section of the optical fiber sensor head and a line linking the discretionary core center and the center of the cross section of the optical fiber sensor head and a bend radius r from the strain amounts ε1-ε4, and finding the curvature distribution of the optical fiber sensor head and the direction of curvature at the position from the distribution of the bend radius r.SELECTED DRAWING: Figure 2