DIODE-PUMPED SINGLE-MODE FLUOROZIRCONATE FIBER LASER FROM THE 4/11/2-]4/13/2 TRANSITION IN ERBIUM

Diode-pumped cw lasing at 2.71, 2.75, and 2.78 μm from an erbium-doped ZBLAN single-mode fiber is reported for the first time. A threshold of 4 mW absorbed power at 792 nm was obtained for the 2.71 μm transition. 3% slope efficiency was obtained with an 80% reflecting output mirror. cw lasing was also observed from the fiber when a tunable pump was scanned across most of the 4I15/2→4I9/2 absorption band. cw lasing observed when pumping around 820 nm indicates that excited-state absorption of the pump from the 4I13/2 may not be necessary for cw operation. However, excited-state absorption of the pump around 810 nm from the 4I11/2 may limit performance.