Thulium-doped nanoparticles and their properties in silica-based optical fibers

摘要

Lasers and amplifiers based on thulium-doped silica fibers require improved spectroscopic properties. In this context, one of the most promising approaches is based on the embedding of thulium ions in nanoparticles of tailored composition and structure. This paper presents various methods used to produce thulium-doped nanoparticles inside silica-based optical fibers. Effects of solution doping method during the elaboration of Modified Chemical Vapor Deposition preform and doping solution composition are studied. A comparison is made between the use of solutions containing LaF3:Tm~(3+) or YAG:Tm~(3+) nanoparticles and aluminum-lanthanum-thulium chlorides. Results show that for similar lanthanum content, lanthanum-thulium chlorides doping allows for similar enhancement of ~3H_4 level of Tm~(3+) than LaF_3:Tm~(3+) doping. Also, effects of aluminum on ~3H_4 lifetime enhancement and inhibition of nanoparticle's formation is discussed.