| 摘要 |
PURPOSE:To make it possible to produce optical fiber having uniformity in the longer direction and a section of any of various shapes, by measuring outer diameters of optical fiber drawn from a preform with a section of any of various shapes in plural directions to calculate the sectional area and controlling the outer diameter of the optical fiber constant. CONSTITUTION:The end of optical fiber preform 30 having a rectangular section is heated and melted by a drawing furnace 1 equipped with a heating element 2 capable of being heated to about 2,000 deg.C and drawn to form an optical fiber 40 having a rectangular section. Then the outer periphery of the optical fiber is coated with a plastic, etc., by a coater 6, further passed through a curing furnace 7 to form a protecting film and wound around a winding drum 8. In an optical fiber drawing device of the above-mentioned constitution, the outer diameters of the optical fiber 40 are measured by a rotary type outer diameter measuring equipment 50 in plural directions. An outer diameter signal and a rotary angle signal outputted from the measuring equipment 50 are inputted to a sectional area calculator 20 to calculate the sectional area of the optical fiber 40. Further difference between a wet target value from a sectional area setting device 90 and the calculated value is detected and winding drum drive circuit 11 is controlled through a PID controller 10. |
