Nonsaturable absorption in alumino-silicate bismuth-doped fibers (original) (raw)

Abstract We report an experimental and theoretical investigation of fluorescence decay and transmission coefficient at∼ 1 μm pumping for a series of bismuth (Bi) doped alumino-silicate fibers with different concentrations of Bi centers. By modeling the experimental data, we show that the excited-state absorption (ESA) and up-conversion (UC) processes are responsible for a growth of nonsaturable absorption and deviation from exponential the fluorescence decay in the fibers with an increase in Bi centers content.