PRODUCTION OF QUARTZ-BASED DOPED GLASS

摘要

PROBLEM TO BE SOLVED: To impart with a uniform dopant concentration distribution to radius direction of an optical fiber. SOLUTION: A preform 5 made of a quartz porous material is immersed in a dopant solution 6 and dried and temporarily sintered in a specified temperature range and preform density is increased to a specified range. Thereby, strength of the preform 5 made of quartz porous material can be enhanced to proper level. Then, the surface is polished and the high concentration part is shaven off by a dopant near the surface. When the bulk density is insufficient, a soot causes crack in polishing and when the bulk density is too high, the surface of the soot is crystallized to often cause cracking. Consequently, a core having uniform concentration distribution is obtained by heat-treating the shoot under definite conditions and polishing the soot.