Amplifying Optical Fiber and Production Method

An amplifying optical fiber, comprising:

• a central core for transmitting and amplifying optical signals, said central core comprising nanoparticles that are doped with one or more rare earth elements;
• and
• an optical cladding for confining optical signals transmitted in said central core, said optical cladding surrounding said central core;
• wherein the volumetric concentration of said nanoparticles in said central core is between about 0.05 percent and 1 percent;
• and
• wherein the weight concentration of said one or more rare earth elements in said nanoparticles is between about 1 percent and 20 percent.

A method for making an optical-fiber preform having a central core and a surrounding optical cladding, the method comprising:

• chemically synthesizing rare-earth-doped nanoparticles in which the weight concentration of rare earth dopants in the nanoparticles is between about 1 percent and 20 percent;
• dispersing the rare-earth-doped nanoparticles in an aqueous solution at a volumetric concentration of between about 0.05 percent and 1 percent;
• and
• impregnating the porous inner layer of a silica tube with the aqueous solution.