Effect of BaF Variation on Spectroscopic Properties of Tm Doped Gallium Tellurite Glasses for Efficient 2.0 μm Laser.

The effects of substitution of BaF for BaO on physical properties and 1. 8 μm emission have been systematically investigated to improve spectroscopic properties in Tm doped gallium tellurite glasses for efficient 2.0 μm fiber laser. It is found that refractive index and density gradually decrease with increasing BaF content from 0 to 9 mol.%, due to the generation of more non-bridging oxygens. Furthermore, OH absorption coefficient (α) reduces monotonically from 3.4 to 2.2 cm and thus emission intensity near 1.8 μm in gallium tellurite glass with 9 mol.% BaF is 1.6 times as large as that without BaF while the lifetime becomes 1.7 times as long as the one without BaF. Relative energy transfer mechanism is proposed. The maximum emission cross section and gain coefficient at around 1.8 μm of gallium tellurite glass containing 9 mol.% BaF are 8.8 × 10 cm and 3.3 cm, respectively. These results indicate that Tm doped gallium tellurite glasses containing BaF appear to be an excellent host material for efficient 2.0 μm fiber laser development.