| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an optical fiber preform by which a high quality preform for a multimode optical fiber can be manufactured at a low cost. <P>SOLUTION: There is provided the method for manufacturing the optical fiber preform G including a trench layer 13 having a refractive index lower than that of pure quartz and a thickness not exceeding the radius of a core 11 at the outside of the core 11 having a refractive index distribution of a graded index. Glass fine particles being the core 11 are deposited by a VAD method and then dehydrated and sintered to form a transparent core glass body G2. The core glass body G2 is drawn into a core glass rod G3, and at the outside of the core glass rod G3, glass fine particles are deposited by an OVD method using a fluorine-containing gas and then dehydrated and sintered, or at the outside of the core glass rod G3, glass fine particles are deposited by the OVD method and then dehydrated and sintered by a fluorine-containing gas to form a transparent glass body G4 including the trench layer 13. A cladding layer 14 is formed on the outer peripheral part of the transparent glass body G4. <P>COPYRIGHT: (C)2013,JPO&INPIT |
