METHOD AND APPARATUS FOR MANUFACTURING PREFORM FOR OPTICAL FIBER

摘要

PURPOSE:To ensure uniform quality by exhausting gas in a reactor in which starting materials are mixed and burned to form and laminate fine glass particles through an exhaust pipe while always controlling the distance from the tip of the exhaust pipe to a laminate of fine particles to a fixed value. CONSTITUTION:An exhaust pipe 5 is fixed in a moving stand 22 which is moved in the directions of arrows 25 by a motor 24 through a screw shaft 23. Photoelectric tubes 26a, 26b are attached to support rods 27, and the rods 27 are fixed on the stand 22. A beam 28 is irradiated from the tube 26a of the light emitting side toward the tube 26b of the light receiving side through windows 29 attached to a muffle 1. The distance from the tip of the exhaust pipe 5 to a base material 4 is equal to the distance from the tip of the pipe 5 to the beam 28. The quantity of light received by the tube 26b of the light receiving side is transduced into voltage, and the stand 22 is moved by the motor 24 so as to keep the voltage constant, thereby moving the pipe 5.