2.074- $\mu \text{m}$ Lasing From Ho3+-Doped Fluorotellurite Microstructured Fibers Pumped by a 1120-nm Laser

We demonstrate 2.074-
$\mu \text{m}$
lasing from Ho
³⁺
-doped fluorotellurite microstructured fibers (FTMFs) pumped by a 1120-nm Yb
³⁺
-doped fiber laser. Ho
³⁺
-doped FTMFs based on TeO
₂
–BaF
₂
–Y
₂
O
₃
glasses are fabricated by using a rod-in-tube method. With increasing the pump power to 253 mW, lasing at 2.074
$\mu \text{m}$
is achieved from a 42-cm-long Ho
³⁺
-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-
$\mu \text{m}$
emissions are also observed from the Ho
³⁺
-doped FTMF.