Rare-earth-doped specialty optical fibers for efficient light sources and photonics applications

Specialty silica optical fibers doped with rare earth ions are heart of fiber lasers, fiber amplifiers and amplified spontaneous emission sources. Such fibers doped with erbium, ytterbium thulium or holmium ions have been prepared by original nanoparticle-doping method. This approach can easily be implemented to conventional MCVD method without additional machinery and high dopant Al/RE ratio and concentration distributed homogeneously in preforms and fibers can be achieved. Fiber lasers based on such fibers exhibited high slope efficiency (up to 81% in the case of holmium-doped fiber laser), high output power (up to 441 W in the case of thulium-doped fiber laser) and low thresholds. Amplified-spontaneous-emission sources based on thulium-holmium-doped fibers or thulium-doped fibers exhibited wide bandwidth of 300-500 nm.