| 摘要 |
PURPOSE: To make the light loss less when cores are bent and to enhance reliability by setting the dimensional of the respective cores at a size of a specific range and specifying the area of the cores at the section and the area of a sheath to a ratio of a specific range. CONSTITUTION: The diameter of the respective cores 1 is 50 to 200μm. Seven or more pieces of the core fibers are discretely partitioned and are integrated by packing a resin of the sheath 2 having the refractive index lower by 0.005 to 0.25 than the refractive index of the resin of the cores 1, by which the ratio of the area of the cores 1 at the section and the area of the sheath 2 is specified to 40:60 to 98:2. Namely, the light loss by bending of the optical fiber increases if the diameter of the cores 1 is larger than 200μm. The transmission loss increases if the diameter of the respective cores 1 is smaller than 50μm. The number of the cores 1 is specified to >=7 pieces at which the arrangement of the cores 1 stabilizes from the need for making the section uniform. The structure is formed by integrating the many cores 1 and the sheath resin enclosing the cores. The light loss is more excellent than heretofore even if the optical fiber having the diameter of the section of about 1mm is bent. |
