| 摘要 |
PURPOSE:To produce the title material with superior loss characteristics and mechanical strength characteristics by covering VAD base material with a thin-walled jacket pipe after which they are heat-fused, covered with a thick-walled jacket pipe, and heat-fused. CONSTITUTION:Porous base material 10 of about 60 mm outside diameter obtd. by a vapor phase axial orientation method is converted into transparent glass to form 25-30 mmphi VDA base material 20. Material 20 is drawn to about 12-16 mmphi thin base material 22. Material 22 is washed with hydrofluoric acid, polished with a flame, and covered with 0.7-2 mm thick, thin-walled jacket pipe 31 made of quartz. One and of pipe 31 is collapsed, pipe 31 is evacuated, and the other end is sealed. Material 22 and pipe 31 are then heat-fused with an oxyhydrogen flame to form intermediate base material 40. Material 40 is further covered with thick-walled jacket pipe 32 made of quartz and heat-fused to give fiber base material 50. |
