Tm~(3+)/Ho~(3+) Co-doped Fluorotellurite Microstructure Fiber for 2.1 μm Lasing

Tm~(3+)/ Ho~(3+)co-doped fluorotellurite microstructure fibers with low concentration of —OH were fabricated by using a rod-in-tube method. Pumped by 1 560 nm fiber laser,electron at Tm~(3+):3H6jump to Tm~(3+)∶3F4,and then energy transfer from Tm~(3+)to Ho~(3+)can occure for the reason of small energy gap( 745 cm- 1) between Tm~(3+):3F4and Ho:5I7,fluorescence at ~ 2. 1 μm can be obtained with the transition from level of Ho~(3+):5I7to Ho~(3+):5I8. By using a 1 560 nm Er~(3+)doped fiber laser as the pump source,an all-fiber lasing at 2 063 nm is obtained from a 18 cm Tm~(3+)/ Ho~(3+)co-doped fluorotellurite microstructure fiber. The corresponding slope efficiency is about 12. 9%,the threshold is 163 m W,and the maximum unsaturated laser output power is 40 m W. The results indicate that the Tm~(3+)/ Ho~(3+)doped fluorotellurite microstructure fiber is a promising gain medium for 2. 1 μm fiber laser.