MANUFACTURE OF POROUS BASE MATERIAL FOR OPTICAL FLUORIDE FIBER

摘要

PURPOSE:To simply obtain a porous base material made of fluoride glass with a very small loss for an optical fiber capable of transmitting infrared rays in a longer wavelength region by treating a porous base material for an optical fiber in a fluorinating atmosphere. CONSTITUTION:A porous base material 6 for an optical fiber consisting of a core 4 and a clad 5 of fine oxide glass particles or solid powder is placed in a container 8. The internal atmosphere of the container 8 is heated to a prescribed temp. with a heater7, and a gas such as F2, HF, NH4F or NH4F.F is fed into the container 8 from a gas cylinder 9 to convert the material 6 into a porous base material for an optical fluoride fiber by fluorination for a prescribed time. An optical fluoride fiber obtd. by drawing the resulting base material can be utilized as an optical fiber transmitting infrared rays in the 2-4mum zone with a small loss.