Toward optimizing gain in Er-Ba nanoparticle-doped optical fibers

Modern commercial erbium-doped fibers are limited in their doping concentrations due to the tendency of Er³⁺ ions to cluster in silicate glasses. Clustering inevitably leads to ion quenching, one major obstacle preventing erbium-doped fibers (EDFs) from scaling to higher laser power near 15XX nm. Here, we present a new, to our knowledge, method for doping erbium into fibers through the use of Er:BaF₂ nanoparticle (NP) precursors. Three optical fibers were produced and investigated. Slope efficiencies up to 0.48 for a 976 nm pumping and a signal wavelength of 1550 nm are demonstrated. This slope efficiency exceeds that of commercial EDFs with comparable or lower active ion concentrations. Adapting the ratio of erbium to barium in the nanoparticle as well as optimizing the number of nanoparticles doped into the fiber is expected to provide significant improvement to these initial results.