QUARTZ BASED GLASS FIBER FOR OPTICAL TRANSMISSION CONTAINING FLUORINE AND P2O5

摘要

PURPOSE:Fibers for optical transmission having a core part of an area having a high refractive index consisting of quartz glass of high purity containing fluorine in a larger amount than P2O5 at weight ratio and P2O5 and glass composition capable of minimizing defects present in glass. CONSTITUTION:Glass optical fibers for optical transmission consisting of a core part of an area having a high refractive index and a clad part, provided on the outer periphery of the core part, and consisting of an area having a low refractive index. The above-mentioned area having a high refractive index consists of quartz glass of high purity containing fluorine in a larger amount than P2O5 at weight ratio and P2O5. P2O5 has two aspects as follows; The contained P2O5 has effect on reduction in production temperature of the optical fibers and suppression of defect formation, but P2O5 promotes defect formation in quartz based tetracoordinate glass due to pentacoordinate P2O5. The coexistence of fluorine and P2O5 and further a larger amount of fluorine permit suppression of defect formation. Preferred ranges of weight ratio are up to about 3wt% fluorine and below about 3wt%, preferably <=1wt% P2O5.