Patent ID: 8675275

Claim:
An amplifying optical fiber, comprising: a central core comprising a core matrix, said central core adapted to transmit and amplify optical signals; and a cladding surrounding said central core and adapted to confine optical signals within said central core; wherein said core matrix comprises (i) additional dopant and (ii) nanoparticles formed of rare-earth-dopant elements and a nanoparticle matrix, said nanoparticle matrix comprising one or more complementary dopant elements; wherein, within said central core, the concentration of said additional dopant is between about 1 weight percent and 10 weight percent; wherein, within said central core, the concentration of said rare-earth-dopant elements is between about 200 ppm and 1000 ppm; wherein, within said central core, the concentration of said complementary dopant elements is between about 0.5 weight percent and 5 weight percent; and wherein the optical fiber's numerical aperture is between 0.10 and 0.18.