Patent ID: 6687439
Filing Date: 2004-02-03
Classification: C03B,H01S

Abstract:
A light-amplifying optical fiber comprising a core region extending along a predetermined axis; and a cladding region, provided on the outer periphery of said core region, having a lower refractive index than said core region;wherein a first doped area with an outer diameter a which includes said predetermined axis and is substantially doped with a rare-earth element exists in a second doped area with an outer diameter b>a which contains an oxide of an element having a valence different from that of a cation constituting a main material, SiO2, of said light-amplifying fiber; and wherein the ratio (a/b) of the outer diameter a of said first doped area to the outer diameter b of said second doped area is 0.1 or more but 0.9 or less.