Patent ID: 9395485
Filing Date: 2016-07-19
CPC Classification: C03B,G02B

Claim Text:
1. A method of manufacturing a glass preform comprising: a first step of vaporizing an alkali metal compound or an alkaline earth metal compound, wherein the alkali metal compound or the alkaline earth metal compound is brought into contact with a hydroxyl group on a surface of porous silica glass manufactured by a thermal oxidation by oxyhydrogen flame; a second step of dehydrating the porous silica glass; and a third step of sintering the dehydrated porous silica glass and forming a transparent glass body, wherein the porous silica glass is doped with an alkali metal oxide or an alkaline earth metal oxide at the same time as the porous silica glass is dehydrated, and during the doping and the dehydration, the entire porous silica glass is evenly heated.