| 摘要 |
PURPOSE:To provide a drawing method of an optical fiber matrix having little longitudinal variation of the outer diameter of a drawn product. CONSTITUTION:An optical fiber glass matrix 1 is transferred slowly downwards in the state where the both ends are held by chucks 3a and 3b through supporting bars 2a and 2b. While the optical fiber glass matrix 1 passes through the inside of a heating furnace it goes through outer diameter changing section and a drawn optical fiber matrix 12 is formed at the outlet of the heating furnace. The heating furnace consists of an upper seal flange 5, a lower seal flange 7, an electric heater 9 placed between the flanges 5 and 7, and an insulating material 10 placed outside of the electric heater 9. The surface temperature of the optical fiber matrix 12 at the outer diameter changing section 11 is monitored by a radiation thermometer 13 placed at a lower side wall of the heating furnace. The outer diameter of the drawn optical glass fiber 12 is always kept at a constant size by controlling either or some combination of the sending speed V1 of the optical fiber glass matrix 1, the drawing speed V2 of the drawn optical fiber 12 and the temperature of the electric heater 9, when the surface temperature of the optical fiber matrix 12 is changed. |
