VERFAHREN UND VORRICHTUNG ZUR HERSTELLUNG EINES GLAS-ROHLINGS FUER OPTISCHE FASERN

摘要

Two gaseous raw glass materials containing dopants to provide different refractive indices and borne by an argon carrier are jetted from the central or inner and first concentric nozzles 11, 12 of a five tip burner 1; an argon shield is supplied through the second concentric nozzle 13, and hydrogen and oxygen are supplied through the third and fourth concentric nozzles 14, 15, respectively. Soot-like glass particles 4 are formed by flame hydrolysis and deposited on the lower end of a start rod 3 which is gradually rotated and withdrawn to thus grow a cylindrical preform 2. The intermixing of the particles formed from the two glass materials produces a preform having a substantially parabolic radial index of refraction distribution, which characteristic is retained in an optical communication fiber formed by sintering and drawing the preform.