PRODUCTION OF POROUS GLASS ROD AND DEVICES THEREFOR

摘要

PURPOSE:In the production of porous glass through the VAD process, a downward gas stream is formed around the path in the reactor to give a porous glass rod of stabilized outer diameter and refractive index distribution. CONSTITUTION:The target is inserted into the reactor 11 until the bottom end reaches a prescribed position and rotated to effect flame hydrolysis through burner 14 to form a porous glass rod 23. As the rod grows, the target 15 is pulled up and simultaneously the reactor 11 is sucked to exhaust gas from the opening 12 and simultaneously a prescribed gas is introduced from the piping 22 through inlet 18 into the path 17 to form a downstream around the path 13. Thus, the gas flow is stabilized in the reactor 11 to give a porous glass rod with stabilized outer diameter and refractive index distribution in the lengthwise direction.