| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an optical fiber preform from which an optical fiber added in the core region with an alkaline metal and having a low transmission loss can be manufactured in a high yield. <P>SOLUTION: A method for manufacturing an optical fiber preform includes an alkaline metal addition step of adding an alkaline metal to a pipe composed of a quartz-based glass, an oxygen molecule addition step of adding oxygen molecules to the glass pipe, and a solid-rendering step of heating and rendering the glass pipe solid. In the optical fiber preform, the core part contains an alkaline metal-added core glass part in which an alkaline metal is added, and the maximum concentration of the oxygen molecule in the core part is≥30 mol-ppb, and the average value of the concentration of the alkaline metal in the core part is≥5 atom-ppm. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
