| CPC G01M 11/33 (2013.01) | 7 Claims |
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1. A bending applying device for measuring a bending loss including at least three mandrels and applying bending to a fed-out optical fiber by winding the optical fiber onto the mandrels,
wherein the mandrels are alternately arranged at predetermined intervals such that outer circumferences of adjacent mandrels in a longitudinal direction of the optical fiber face each other in a non-contact manner,
a diameter of the optical fiber is D,
a radius of the mandrel is r,
in a plane orthogonal to rotation axes of the mandrels, a direction connecting an upstream-side contact point and a downstream-side contact point is a first direction, the upstream-side contact point being a point where the optical fiber starts to come into contact with a mandrel located at the center among the three mandrels having the same diameter and continuously arranged along the longitudinal direction of the optical fiber, the downstream-side contact point being a point where the optical fiber wound around the mandrel at the center starts to move away from the mandrel located at the center,
a distance between surfaces of the adjacent mandrels in the first direction is d,
an interval between the adjacent mandrels in the first direction is 2r+d,
a direction orthogonal to the first direction in the plane orthogonal to the rotation axes of the mandrels is a second direction,
an interval between the adjacent mandrels in the second direction is s, and
an angle θ between the second direction and a common internal tangent of the adjacent mandrels as viewed from a center position of the optical fiber is 0 degrees or more and 45 degrees or less, and
the formed angle θ satisfies following formula
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