| 摘要 |
PURPOSE:To obtain an optical fiber having high strength over its long size, by immersing a base material for an optical fiber before drawing in hydrofluoric acid, polishing the surface of the material with an oxyhydrogen flame, and drawing the material. CONSTITUTION:A base material for an optical fiber before drawing is immersed in hydrofluoric acid having 5-30wt% concn. for 0.5-5hr. The hydrofluoric acid may be mixed with sulfuric acid, nitric acid or the like. The treated base material is polished once or more with an oxyhydrogen flame so as to make the surface temp. 1,500-2,300 deg.C. The polished base material is drawn at about 2,300 deg.C in a carbon resistance furnace. The resulting optical fiber has high fiber strength which can not be attained by a single surface treatment. |
