OPTICAL FIBER

摘要

An optical fiber containing an alkali metal and capable of reducing Rayleigh scattering loss is provided. An optical fiber has a core and a cladding made of silica glass and enclosing the core. The cladding contains fluorine and has a refractive index lower than the refractive index of the core. The core contains first group dopants selected from the group of Na element, K element, or a compound thereof at an average concentration of 0.2 ppm or more and 10 ppm or less. The core also contains second group dopants for reducing the viscosity of silica glass and having a diffusion coefficient of 1×10−12 cm2/s or more and smaller than the diffusion coefficient of the first group dopants, by an average concentration of 0.2 ppm or more at a temperature of 2000° C. to 2300° C.

主权项

1. An optical fiber comprising:
a core made of silica glass containing a first group of dopants by concentration of 0.2 ppm or more on the average, the first group of dopants consisting of Na element, K element, or any compound thereof, and a second group of dopants by 0.2 ppm or more on the average, the second group of dopants decreasing the viscosity of silica glass and having a diffusion coefficient of 1×10−12 cm2/s or more and smaller than the diffusion coefficient of the first group dopants at a temperature of 2000° C. to 2300° C.; and a cladding formed around the core and made of silica glass containing fluorine, the cladding having a refractive index lower than the refractive index of the core.