| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an optical fiber base material, wherein a thickness of a OH barrier is diminished, a self-condensation of a quartz tube is suppressed and also OH impregnating in a core layer is effectively cut off, by laminating a multi-layer OH barrier formed by materials having different permeabilities. <P>SOLUTION: The optical fiber base material 220 is composed of a cylindrical quartz tube 240 functioning as a base plate for forming the optical fiber base material, the first barrier 233 that is laminated on an inner peripheral face of a quartz tube and cuts off OH impregnating into the optical fiber base material, the second barrier 232 that is laminated on the first barrier and has a higher permeability than the first barrier, the third barrier 231 that is laminated on the second barrier and has a lower permeability than the second barrier, a clad layer 222 on an inner side of the third barrier and a core layer 221. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |
