| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing an optical fiber preform corresponding to producing a large-sized optical fiber preform when producing the optical fiber preform by an outside deposition method such as an OVD method and the like and transparently vitrifying a silica glass porous body without causing cracking, exfoliation, dislocation and the like in a valid portion of glass. <P>SOLUTION: In the method for producing the optical fiber preform, a porous glass preform 1 having a valid portion 10 to be used for the production of an optical fiber and a first invalid portion 11 and a second invalid portion 12 at both the end sides of the valid portion 10 by depositing the silica glass porous body 5 on the outer peripheries of a glass rod 2, a first dummy rod 3 and a second dummy rod 4 is produced, the porous glass preform 1 is heated to transparently vitrify the silica glass porous body 5, and in this case the position of at least a part in either or both of the first invalid portion 11 and the second invalid portion 12 among the silica glass porous body 5 is dislocated to the first dummy rod 3 or the second dummy rod 4 in the center axial direction of the glass rod so that the stress between the glass rod 2 and the silica glass porous body 5 is relaxed. <P>COPYRIGHT: (C)2013,JPO&INPIT |
