METHOD FOR DRAWING PREFORM FOR PHOTOWAVEGUIDE OF FLUORIDE GLASS

摘要

PURPOSE:To draw preform into a given outer diameter without causing devitrification and to make mass production possible. CONSTITUTION:Preform 6 for photowaveguide of fluoride glass of ZrF4-BaF4- LaF3-AlF3-NaF system is set in the center of a transparent container 4 made of quartz glass. The preform 6 for photowaveguide of fluoride glass is heated to about 300 deg.C by using a burner 1 as a mobile heating source while sending an inert gas (nitrogen gas) from an inlet 8 to an outlet 9 by regulating a flow rate with a mass flow controller 3 and rotating the preform at a given number of revolutions and drawn. The drawing is carried out by confirming the outer diameter and a drawing point by an outer diameter measuring device 2.