Fluorescence and attenuation properties of Er3+ -doped phosphate-glass fibers and efficient infrared-to-visible up-conversion

Fluorescence spectra of phosphate glasses with different erbium doping have been measured. The flourescence intensity reaches its maximum at an Er³⁺-doping concentration of 0.75 mol%. When the Er³⁺ doping exceeds 0.75 mol%, the fluorescence intensity decreases due to concentration quenching. The attenuation at 1.53 µm of the fiber is 12.8 db/m. The fluorescence up-conversion of 1.064 µm Nd:YAG laser pulses into intense green 547 and 667 nm light in the fiber has been measured. The fluorescence output power of green (547 nm) and red (667 nm) light is 178 and 42 W, respectively with an excitation power of 1 W. The two signals are referred to as⁴ S _3/2 ⁴ I _{1 5/2} and⁴ F _9/2 ⁴ I _{1 5/2} transitions through two-photon absorption fluorescence.