| 摘要 |
A method for manufacturing an optical fiber base material includes producing glass fine particles through a hydrolysis of a glass material gas in a flame created by an oxidizing gas and a combustible gas. The method uses a burner including: a central gas discharge port that ejects a gas containing an oxidizing gas; a plurality of small-diameter gas discharge ports that are arranged in a concentric circle with the central gas discharge port so as to externally surround the central gas discharge port, where the plurality of small-diameter gas discharge ports eject a gas containing an oxidizing gas; a combustible gas discharge port that is concentrically arranged with the central gas discharge port so as to externally surround the central gas discharge port, where the combustible gas discharge port has the plurality of small-diameter gas discharge port arranged therein and the combustible gas discharge port ejects a combustible gas; and an oxidizing gas discharge port that is concentrically arranged with the central gas discharge port so as to externally surround the combustible gas discharge port, the oxidizing gas discharge port ejecting an oxidizing gas. Here, a relation of V 1 > V 2 >V 3 > V 4 is satisfied where V 1 denotes a gas flow speed at the central gas discharge port, V 2 denotes a gas flow speed at the plurality of small-diameter gas discharge ports, V 3 denotes a gas flow speed at the combustible gas discharge port, and V 4 denotes a gas flow speed at the oxidizing gas discharge port. |
