Spectroscopic and laser properties of Ho 3+ doped lanthanum‐tungsten‐tellurite glass and fiber

The spectroscopic properties of 2-μm emission in Ho3+-doped lanthanum–tungsten–tellurite glasses with different Ho2O3 concentrations were investigated. The strongest emission was observed in a glass sample doped with 0.5 mol% Ho2O3, with a fluorescence lifetime of 3.16 ms and a emission cross section of 6.97×10−21 cm2 at 2040 nm. For this composition, no obvious changes in the emission properties and fluorescence lifetime were observed at temperatures of 295–350 K. Using this 60TeO2–30WO3–9.5La2O3–0.5Ho2O3 glass as a core material, Ho3+-doped double cladding fiber with a core diameter of 14 μm and a numerical aperture of 0.12 was developed. A maximum laser output power of 34 mW at 2040 nm was achieved with a 9-cm-long Ho3+-doped tellurite glass fiber. To the best of our knowledge, this study presents the first report on the 2-μm laser output from a Ho3+-doped tellurite oxide glass fiber resonantly pumped by a 1.94 μm Tm-fiber laser.