DISPERSION CONTROLLING OPTICAL FIBER AND METHOD FOR PRODUCTION OF LARGE DIAMETER PREFORM THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a dispersion controlling optical fiber and a large diameter preform. SOLUTION: The dispersion controlling optical fiber 300 includes a core 310 comprising an SiO2-GeO2-P2O5 three-component system and a clad 320 comprising an SiO2-GeO2-P2O5-chlorofluorocarbon four-component system. The large diameter preform for the optical fiber is produced through a clad vapor- depositing step in which SiO2, GeO2, P2O5 and chlorofluorocarbons are vapor- deposited on the inside of a vapor deposition tube to form a clad layer and a core vapor-depositing step in which SiO2, GeO2 and P2O5 are vapor-deposited on the inside of the clad layer to form a core layer.