PRODUCTION OF FLUORINE-DOPED QUARTZ GLASS

摘要

PURPOSE:To provide a process for the production of a fluorine-doped quartz glass having stable and high specific refractive index difference at high deposition rate. CONSTITUTION:A fluorine-doped quartz glass is formed on the circumference of a starting member 10 by plasma outer deposition method. The deposition process is carried out by placing a plasma torch opposite to the starting member 10 and perpendicular to the length of the member and supplying a fluorine-based gas coaxially with a plasma flame 11 ejected from the plasma torch simultaneously with the supply of a quartz glass raw material gas 15 into the plasma flame 11 from a side opposite to the moving direction of the starting member 10 relative to the plasma flame 11. Fine powder of quartz glass is temporarily deposited behind the position where the plasma flame 11 collides with the starting member 10 and the powder is doped with fluorine decomposed in the plasma flame 11 and converted to transparent glass by contacting the powder with the plasma flame 11.