OPTICAL FIBER FOR OPTICAL AMPLIFYING AND PRODUCTION METHOD THEREFOR

摘要

An optical fiber for optical amplifying, provided with a structure for implementing flat gain characteristics or oscillation characteristics in wider wavelength bands, and a production method therefor. The optical fiber for optical amplifying is provided with a second dope region containing an optical axis center-containing first dope region and having an outer diameter larger than that of the first dope region. At least any one of Al2O3, P2O5, Y2O3 and B2O3 are added into the second dope region as oxides of elements having valences different from those of cations constituting the main materials of the above optical fiber. At least any of Er, Nd, Tm, Yb, Pr as rare earth elements, in addition to the above oxides, are added into the first dope region.