| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To obtain an optical fiber excellent in both of hydrogen resistance characteristics and transmission characteristics. <P>SOLUTION: When a clad 2 comprises a region as an inner clad 2a where light passes and the rest region as an outer clad 2b, at least both of the core 1 and the inner clad 2a are doped with fluorine to control the irreversible increase of the loss in a 1,550 nm band caused by intrusion of hydrogen to≤0.01 dB/km. The optical fiber is obtained, for example, by doping the optical fiber with fluorine in such a manner that the average effective concentration of fluorine defined as the weighted average by the intensity of the transmitted light is controlled to 0.08 to 2.5%. Further, by doping the almost all region where light passes with fluorine by≥0.03 wt.%, the obtained optical fiber has more improved hydrogen resistance characteristics. <P>COPYRIGHT: (C)2003,JPO</p> |
