PRODUCTION OF PREFORM FOR OPTICAL FIBER AND DEVICE THEREFOR

摘要

PURPOSE:To obtain preform for high-quality optical fiber, by discharging an exhaust gas while spraying a gas from the inside of the tip part of an exhaust pipe at the side of a reactor and by piling glass fine particles on a starting material and a core rod. CONSTITUTION:A porous glass preform 5 is produced by constitution wherein a combustion burner 2, a starting material 3 and an exhaust pipe 4 are set in a reactor 1. The tip part of the exhaust pipe 4 has a double structure and a gas feed opening 7 is set in the double structure cylinder. A gas is fed from the feed opening 7 to the tip of the exhaust pipe and approximately uniformly blown off through a porous inner cylinder 6 into the exhaust pipe. Under these constitution, SiCl4 as a raw material and H2 and O2 as a fuel are to the combustion burner 2. Glass fine particles SiO2 are formed in flame 8 formed by the combustion burner 2 and piled on the tip of the starting material 3 so that the porous glass preform is being produced.