INFRARED OPTICAL FIBER AND PRODUCTION THEREOF

摘要

PURPOSE:To improve mechanical characteristics, bending characteristics and exit optical characteristics by specifying the compsn. ratio of silver chloride (AgCl) and silver bromide (AgBr) to 30 to 70wt.% AgCl and the average grain size to <=5mum. CONSTITUTION:The silver chloride and the silver bromide are compounded to the compsn. ratio of 30 to 70wt.% silver chloride and a single crystal is formed by a Bridgman method. A preform 2 is a base crystal formed by molding the single crystal to a cylinder of about phi8mm. An extrusion temp. is thereafter set at 150 to 220 deg.C and after the temp. stabilizes, 5 to 15 tons/cm<2> pressure is applied to the preform 2 by a hydraulic press and the IR optical fiber 1 is produced while an additional load is applied by a weight 8 on the IR optical fiber 1. The IR optical fiber having 8.5kg/cm<2> tensile strength and <=5mum grain size is obtd. under >=7 tons/cm<2> extrusion pressure. The IR optical fiber having the high mechanical strength to withstand 100 times of repetitive bending at 10mm radius and 2000 times of repetitive bending at 20 mm radius is obtd. in this way.