Search International and National Patent Collections

1. (WO2018079341) PRODUCTION METHOD FOR OPTICAL FIBER PREFORM

Pub. No.:    WO/2018/079341    International Application No.:    PCT/JP2017/037538
Publication Date: Fri May 04 01:59:59 CEST 2018 International Filing Date: Wed Oct 18 01:59:59 CEST 2017
IPC: C03B 37/018
C03B 8/04
C03C 25/68
Applicants: FUJIKURA LTD.
株式会社フジクラ
Inventors: NAGASU Katsubumi
長洲 勝文
Title: PRODUCTION METHOD FOR OPTICAL FIBER PREFORM
Abstract:
This production method for an optical fiber preform is for producing an optical fiber that has a core formed from silica glass and a cladding formed on the outer periphery of the core. The production method for an optical fiber preform comprises: an etching step of etching-processing, in a chamber, the surface of a core preform which is to become the core with a plasma flame; a depositing step of depositing fine glass particles on the etching-processed surface of the core preform to form an external layer which is to become the cladding, and obtain a porous preform while the core preform is still inside the chamber; and a sintering step of heating and sintering the porous preform. In the depositing step, the depositing of the fine glass particles via the supply of a starting material gas is repeated multiple times, thereby forming the external layer. Of the multiple times the depositing of the fine glass particles is performed, at least during the first time, the flow rate of the starting material gas relative to the steady-state value is 50% or lower, and the temperature on the etching-processed surface of the core preform when starting the depositing step is 50°C or higher.