| 摘要 |
PURPOSE:To obtain the title material contg. very little residual water and having superior light transmission charactristics by heating a tubular core clad structure to a high temp. in a chlorine or chloride-contg. atmosphere to turn the structure into a rodlike one. CONSTITUTION:Tubular core clad structure 1 obtd. by forming a high purity glass film inside a quartz tube is locally heated to about 1600-1800 deg.C with external burner 2 while rotating structure 1. By moving burner 2 back and forth while feeding Cl2-contg. oxygen into the tube, the inside diameter of the tube is reduced gradually. At the time of the final burner movement, by stopping feed of the gas the tube is compacted to obtain a base material for optical fiber contg. very litter water. SiCl4, PoCl3, GeCl4, BCl3, CCl4, NoCl or the like may be used in place of the Cl2 gas to give similar effects. |
