Enhanced broadband near-infrared emission and energy transfer in Bi-Tm-codoped germanate glasses for broadband optical amplification.

Bi-Tm-codoped, and Tm- and Bi- singly doped germanate glasses were prepared, and their luminescent properties were investigated. Intense broadband near-IR emission with FWHM of 300 nm was observed in the Bi-Tm codoped glass. The emission intensity of Tm(3+):(3)H(4)-(13)F(4) and (3)F(4)-(13)H(5) transitions in the Bi-Tm-codoped glass was highly increased and reduced, respectively. The fluorescence lifetime of Tm(3+) at 1470 nm increased from 204 micros to 301 micros after codoping. These should be due to the efficient energy transfer from Bi-related centers to Tm(3+) ions. The highest energy transfer efficiency is estimated to be approximately 50%.