摘要 |
In an optical fiber preform fabrication method having the steps of decomposing a glass raw material in a flame so that fine glass particles are produced; depositing the fine glass particles on a seed rod to form a porous preform; and consolidating the porous preform into a transparent optical fiber preform, use is made of a burner having a raw material supply orifice for supplying the glass raw material and a plurality of flame forming orifices disposed around the raw material supply orifice sequentially for forming a plurality of flames, respectively. The flame speed Vk of a kth flame, the flame speed Vk+1 of a (k+1)th flame surrounding outwardly of the kth flame and the flow speed Vm of the glass raw material are determined in a suitable manner. The glass raw material is supplied to the maluti-flame produced by the burner in which the kth flame is positioned rearwardly of the (k+1)th flame to synthesize the fine glass particles. |