| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a producing method and the like of a preform where the preform to produce an optical fiber added with a rare earth element and a P element can be produced stably and efficiently. <P>SOLUTION: The producing method of the preform comprises a first step to deposit glass containing P<SB>2</SB>O<SB>5</SB>on the inside wall of a quartz pipe and a second step to deposit glass containing the rare earth element and not containing P<SB>2</SB>O<SB>5</SB>on the inside wall of the quartz pipe. The preform added with the rare earth element at a core part is produced by performing the first step and the second step alternately and repeatedly. In the producing method of the preform, it is favorable that the rare earth element is an Er element, an F element is added in the quartz pipe, the quartz pipe is heated to 1,500°C or lower in the first step and the quartz pipe is heated to 1,800°C or higher in the second step. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
