| 摘要 |
PURPOSE:To improve the yield of production and to improve the radiation resistant characteristic of an image fiber by adding fluorine and chlorine to the pure quartz glass of a core part, thereby obviating the deterioration of image quality and enabling the easy production of the image fiber. CONSTITUTION:The core part 1 consists of the pure quartz glass and is formed by adding the chlorine and fluorine thereto. The chlorine is a dopant to raise the refractive index and the fluorine is a dopant to lower the refractive index, by which the refractive index of the core part 1 is lowered to about the refractive index of the pure quartz. A clad part 2 consists of the pure quartz glass added with the fluorine. As a result, the difference in the melting temp. between the core part 1 and the clad part 2 decreases and, therefore, the setting of such temp. conditions under which bubbles are not generated at the time of drawing is facilitated and the yield of the production is improved. On the other hand, the melting temp. of the core part 1 is lowered but the refractive index thereof is not lowered and, therefore, the refractive index with the clad part 2 is maintained and the degradation in image quality is averted. |
