OPTICALLY ATTENUATING OPTICAL FIBER

摘要

PROBLEM TO BE SOLVED: To provide an optical attenuator which has superior characteristic stability at a low cost by reducing the influence of a clad mode that is generated at the time of connection. SOLUTION: This optically attenuating optical fiber consists of a core 1 and clads 2 and 3 which surround the core 1 and are lower in refractive index at least nearby the core 1 than the core 1, and contains a dopant for attenuating a light signal in the core or clad part 2 nearby the core, and the high refractive index clad part 3 which has a refractive index larger than the refractive index nearby the core is installed partially in the clads 2 and 3 not nearby the core. Further, a part or the whole high refractivel index clad part 3 contains the dopant which attenuates the light signal. This optically attenuating optical fiber contains the dopant which attenuates the light signal partially in the clads 2 and 3 not nearby the core.