| 摘要 |
PURPOSE:To make it possible to secure measuring accuracy, by providing two bending apparatuses for imparting bendings different in radius of curvature to an optical fiber to be measured and arranging two members having circular arc cross-sections same in radius of curvature to the apparatus for imparting bending with large radius of curvature in a predetermined manner. CONSTITUTION:The wavelength variable light source 12 controlled by a control/ operation apparatus 10 and a light detector 14 for applying output to said apparatus 10 are provided. The photometric fibers 16, 20 of measuring devices are held by holders 18, 22 and an optical fiber 28 to be measured is held by holders 24, 26. A cut-off wavelength is measured from the comparison optical outputs obtained when bending with large radius of curvature and that with small radius of curvature were applied to the fiber 28. Bending with large radius of curvature is imparted by large rollers 30, 32 and the roller 32 is held by a guide groove 34A in a slidable manner. The rollers 30, 32 have the same radius of curvature and arranged so as to impart the length of a bent part equal to one circumference of circle in total when the fiber 28 is bent in an S-shape. By this method, measuring accuracy can be secured and workability can abe enhanced. |
