2875 nm Lasing From Ho3+-Doped Fluoroindate Glass Fibers

Ho
³⁺
-doped fluoroindate glass fibers (FIGFs) based on InF
₃
-GaF
₃
-ZnF
₂
-BaF
₂
-SrF
₂
-YF
₃
-LiF-PbF
₂
glasses were fabricated by using a rod-in-tube method. By using a 92-cm-long Ho
³⁺
-doped FIGF as the gain medium and a 1120-nm fiber laser as the pump source, lasing at 2875 nm was obtained for a threshold pump power of 278 mW. By further increasing the pump power to 1224 mW, the obtained maximum output power was about 54.5 mW. The corresponding slope efficiency was about 6%. To the best of our knowledge, this is the first time to report lasing at 2875 nm from Ho
³⁺
-doped FIGFs.