OPTICAL FIBER PREFORM HAVING OH INTERCEPTING LAYER AND THE METHOD THEREOF

摘要

PURPOSE: An optical fiber preform is provided which is prepared by modified chemical vapor deposition processing. The optical fiber preform has low diameter ratio b/a to improve refractive index distribution of DC-SM optical fiber and also materializes to low loss. CONSTITUTION: An optical fiber preform is characterized by; being located between one tube and cladding layer; more having the first intercepting layer to prevent OH functional group contained one tube deposited by material having low OH diffusion coefficient to seep into cladding layer; refractive index of core layer higher than that of cladding layer and increasing as center part goes on higher and higher. A method for preparing optical fiber preform comprises the steps of; forming the first intercepting layer deposited by material having low OH diffusion coefficient; forming the cladding layer at the inside of the first intercepting layer; and forming the core layer deposited refractive index as center part goes on higher and higher which is transmitted light signal.