| 摘要 |
PROBLEM TO BE SOLVED: To suppress rotation of the plane of polarization due to oscillation of an optical fiber and to reduce the occurrence of birefringence due to an influence of a stress with respect to an optical fiber cable where an optical fiber is protected by a protective tube. SOLUTION: Since an optical fiber 12 is preliminarily aligned with a protective tube 11 and is set, a gap 10a between the optical fiber 12 and the protective tube is uniformly formed. This gap 10a is packed with resin 25. Since resin which is semi-liquefied or solid and causes a stress little to the optical fiber 12 is used as this resin 25 packed in the gap 10a, oscillation of the optical fiber due to the impact from the outside is suppressed as much as possible. Thus, rotation of the plane of polarization is suppressed to perform photometry with a high precision. Since the optical fiber 12 is coated with resin 25, it is strong against the stress, and the occurrence of birefringence is reduced. With respect to this point, photometry is performed with a high precision also. |
