PREPARATION OF LOWWOH OPTICAL FIBER MATRIX

摘要

PURPOSE:To easily provide a low-OH optical fiber matrix without reducing its productivity by a method wherein during the growing of a porous glass matrix a chlorine atmosphere treatment is performed so as to control migration of OH gp. into the porous glass matrix. CONSTITUTION:A flame-hydrolysis burner 1 is used to produce a flame 2 including fine glass particles. The flame is used to grow a porous glass matrix 3 on the target 4 which is moving in the arrow direction 5 while revolving itself in the arrow 6 direction. Under this condition, a chlorine-containing oxidizing gas is introduced in the arrow direction 8 from the inlet of the gas-jet device 7 installed around the flame 2. As shown by the arrow 8', the chlorine-containing oxidizing gas is jetted from the periphery of the flame onto the flame so that such a gas is diffused and permeated into the flame. This causes H2O and OH ions in the flame to react with the chlorine-containing oxidizing gas. In this manner, H2O and OH ions are prevented from migrating into the porous glass matrix.