| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method for producing a rare earth doped optical fiber effective for suppressing photodarkening. <P>SOLUTION: An optical fiber preform is allowed to contain 10-100 wtppm of an OH group. When the optical fiber preform is drawn to form an optical fiber, the drawing condition satisfies the expression: 0.5≤α<SB>f</SB>/α<SB>p</SB>≤0.95, whereinα<SB>p</SB>represents OH absorption loss calculated based on the OH concentration distribution of the optical fiber preform before drawing and electric field strength distribution, andα<SB>f</SB>represents OH absorption loss of the optical fiber after drawing. The OH group in the optical fiber preform is preferably distributed in a core part to which rare earth has been added. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
