2.074-μm Lasing from Ho³⁺-Doped Fluorotellurite Microstructured Fibers Pumped by a 1120-nm Laser

We demonstrate 2.074-μm lasing from Ho³⁺-doped fluorotellurite microstructured fibers (FTMFs) pumped by a 1120-nm Yb³⁺-doped fiber laser. Ho³⁺-doped FTMFs based on TeO₂-BaF₂-Y₂O₃ glasses are fabricated by using a rod-in-tube method. With increasing the pump power to 253 mW, lasing at 2.074 μm is achieved from a 42-cm-long Ho³⁺-doped FTMF. With further increasing the pump power to 1015 mW, a maximum unsaturated power of 98 mW is obtained, and the corresponding slope efficiency is up to 12.4%. In addition, relatively strong 1.2- and 2.9-μm emissions are also observed from the Ho³⁺-doped FTMF.