METHOD OF PRODUCING AN OPTICAL WAVEGUIDE MATERIAL

摘要

A rod-in-tube method for producing an optical waveguide material is disclosed, in which a hydrogen-free compound containing at least one selected from the group consisting of C, N, O, S, Se and at least one of halogens is passed in a vapor state through the clearance between a silica glass cladding material and a silica glass core material inserted thereinto prior to their fusion to vapor-phase treat the surfaces of these two materials under heating up to a high temperature for removing impurities existing thereat as volatile halogenides and these vapor-phase treated two materials are immediately fused by heating up to a higher temperature to be pulled. The thus produced optical waveguide material is improved in the boundary condition of these two materials fused and therefore very low in light attenuation.