OPTICAL FIBER PREFORM HAVING OH BARRIER AND MANUFACTURING METHOD THEREOF

摘要

An optical fiber preform having a substrate tube, a cladding layer and a cor e layer further includes a first barrier layer deposited by a material having a low OH diffusion coefficient between the substrate tube and the cladding layer, wherein the first barrier layer is for substantially preventing OH contained in the substrate tube from being diffused into the cladding layer. The optical fiber preform further includes a second barrier layer formed by depositing a material having a low OH diffusion coefficient between the cladding layer and core layer, for substantially preventing OH which has bee n diffused into the cladding layer from the substrate tube from being diffused further into the core layer. Outer and inner OH barriers containing no P2O5 are deposited between the substrate tube and the cladding layer and between the cladding layer and the core layer in a deposition process, such that OH can be effectively prevented from being diffused from the substrate tube to the core layer in a core deposition process, a collapsing process or a closi ng process.