| 摘要 |
PURPOSE:To prevent diffusion and attack of H2 and to obtain stable light transmission characteristics for a long term by providing the outside of light transmitting part of a core and a clad with an F-contg. quartz glass layer for preventing diffusion of H2 from outside and providing its inside with an F-not contg. quartz glass layer. CONSTITUTION:Quartz glass layers 4.4A.4B contg. F for preventing diffusion of H2 from the outside are provided on the outside of the part of a core 1 and a clad 2, etc. for transmitting light, and pure quartz glass layers 3.3A.3B not contg. F are formed on the inside of said layers 4.4A.4B. The use of said F- contg. layers prevents H2 generated by heat, UV rays, radiation, or the like and water vapor from diffusion to the light transmission part and attack and deterioration of it. The H2 diffusion prevention effect is made higher the thicker the layer 4.4A.4B becomes, and the layer 3.3A.3B made of pure quartz glass serves for enhancing said effect. As a result, the obtained optical fiber is not attacked by H2 and can maintain transmission characteristics stable for a long term. |
