Novel Tm3+/Ho3+ Co-Doped Tellurate Glass with High Emission Cross Section for 2μm Fiber Lasers

A modified melt quenching technique was used to prepare new Tm3+/Ho3+ co-doped TeO2-Ta2O5-La2O3 (TTL) glass with high emission cross section. By standing the traditional tube furnace sideways, the melt quenching method is optimized to produce tellurate glass efficiently and simply. The performance of the glass system is studied in detail, and the possibility of this glass system as a 2.0 μm fiber laser material is obtained. The glass system was obtained by test analysis to have large refractive index (nd>2.01) and density (>5.28 g/cm3), excellent mechanical properties (>4.5Gpa). TTL5 glass was obtained with excellent glass transition temperature (Tg>439 °C) and good resistance to crystallization based on thermodynamic analysis(ΔT>170 °C). In addition, the bonding structure was studied and maximum phonon energy of TTL5 glasses was determined to be ∼669 cm−1 by Raman. The SEM micrographs show well the surface micromorphology of TTL3 and TTL5, and EDAX verifies that the results of elemental analysis of this system of glasses are reliable. Fluorescence spectroscopy demonstrated a TTL5 series of samples with 2.0 μm strong emission. Finally, the absorption emission cross-sections of Ho3+ were calculated to be as high as7.92×10−21 (at 1963 nm) and 12.301×10−21 (at 2061 nm), respectively, with a maximum gain factor of 2.75 cm−1. The results show that this new TTL series glass has high thermal stability, low phonon energy, and efficient 2.0 µm fluorescence, extending the tellurite glass system and being a good candidate for obtaining efficient 2.0 µm emission.