FABRICATION METHODS OF DOPED SILICA GLASS AND OPTICAL FIBRE PREFORM BY USING THE DOPED SILICA GLASS

摘要

Doped SiO2 glass is made by subjecting an easily oxidisable SiO2 cpd. to thermal oxidn. or flame hydrolysis to form SiO2 glass fine particles; dissolving a dopant oxide into the particles by oxidising a gas which forms doped SiO2 on the particle surfaces; and sintering to vitrify the particles. (I) pref. comprises an oxidisable Si cpd.; an oxidisable dopant precursor; and water vapour or O2. The doped SiO2 glass is pref. formed at 500-1200 deg.C, 500-1000 deg.C in the case of thermal hydrolysis and 800-1200 deg.C in the case of thermal oxidn. Used in prodn. of optical fibre preforms. Pref. the doped SiO2 glass particles are deposited and sintered on a rotating starting material, the rotating axis of which is inclined at 5-90 deg. to the blow-off direction.