High-Efficiency Nd³⁺-Doped Phosphate Fiber Laser at 880 nm

Spectroscopic properties of Nd3+-doped phosphate glass for three-level laser were investigated for the first time. A 60 nm blue-shift of the three-level transition fluorescence spectrum was achieved by changing the host material from traditional silica glass to phosphate glass. An 880-nm all-fiber laser with a world-record slope efficiency of 42.8% was demonstrated with 25-cm-long 0.25-wt.% Nd3+-doped phosphate fiber. Our research shows that Nd3+-doped phosphate glass is a high-efficiency material for laser operation below 900 nm.