| 摘要 |
PURPOSE:To reduce residual stress in core of optical fiber consisting of quartz glass and core in production of quartz-based optical fiber. CONSTITUTION:In producing a glass preform by dehydrating a porous preform consisting essentially of quartz and vitrifying transparently, the porous preform is heat-treated in an atmosphere comprising a halogen-containing gas in the dehydrating process and/or the transparently vitrifying to add 0.1-1wt.% halogen to quartz glass and the prepared glass preform is used as core of optical fiber to produce glass preform for optical fiber. Chlorine is preferable as the halogen. The core formed in this way has small residual stress and variability of specific refractive index difference, lambdac, MFD, etc., from set values is small. |
