Enhanced near-infrared emission and broadband optical amplification in Yb-Bi co-doped germanosilicate glasses

Yb-Bi co-doped germanosilicate glasses were prepared and their optical properties and optical amplification were investigated. Compared with single Bi-doped glasses, apparent enhancement in emission intensity, luminescence lifetime and optical gain was observed in Yb-Bi co-doped glasses with an excitation at 980 or 808 nm. The slope of the optical gain coefficient with the 808 nm excitation is much higher than that with 980 nm. The influences of Yb co-doping on the photoluminescence and gain properties of glasses with excitation at 808 nm were investigated and discussed. The highest gain coefficient at 1300 nm reaches 4.34 dB cm^-1 and 1.08 dB cm ^-1 for the 808 nm and 980 nm excitations, respectively. The stimulated emission cross-section of the Yb-Bi co-doped glass with the 808 and 980 nm excitations was also estimated. Yb-Bi co-doped germanosilicate glasses are available for broadband amplification with either 980 or 808 nm excitation.