| 摘要 |
PURPOSE:To measure the specific refractivity of an optical fiber by providing a light-collecting optical fiber large in core diameter and NA at the side of the light incidence end of the optical fiber to be measured. CONSTITUTION:Light emitted from light source 1 is passed through object lenses 2a and 2b and light attenuator 3 located between said lenses. Further, when this light is passed through optical fiber 4, the light incidence conditions of optical fiber 4 are relieved by providing light-collecting optical fiber 12 at the side of light incidence end 5a of optical fiber 4, and light power from light emission end 5b is made proportional to the specific refractivity of optical fiber 4. Light-collecting optical fiber 12 should have the core diameter and NA greater than those of optical fiber 4 to be measured by several - tens times. Thus, light is made to inject optical fiber 4 with the stable quantity of the light. |
