PRODUCTION OF POLYCRYSTALLINE OPTICAL FIBER FOR INFRARED LIGHT

摘要

PURPOSE:To obtain a polycrystalline optical fiber for IR light which is straight and is free from defects such as bending and waving by extruding the optical fiber for IR light perpendicularly downward while exerting tension thereto in the same direction. CONSTITUTION:A weight 7 is mounted to the end of the optical fiber 6 for IR light right after the fiber is extruded and exposed from a die 1. Then the tension equivalent to the weight 7 is perpendicularly downward exerted to the extruded fiber 6. The extruded fiber 6 is made entirely free from bending by making preliminarily the extruding hole direction of the die 1 to coincide with the perpendicular direction. The weight 7 is particularly effective for correcting the bend when the plasticity of the fiber 6 right after the extrusion is large. The trouble in the case of protecting the polycrystalline optical fiber with a pipe, etc. is thus eliminated if such fiber is used as an optical waveguide to be used for a laser surgical knife, laser beam processing machine, etc. using laser light of high-density energy.