Advanced bismuth-doped lead-germanate glass for broadband optical gain devices

We fabricated a series of glasses with the composition 94.7GeO2-5Al2O3-0.3Bi2O3PbO =0–24 mol. % . Characteristic absorption bands of bismuth centered at 500, 700, 800, and 1000 nm were observed. Adding PbO was found to decrease the strength of bismuth absorption. The addition of 3%–4% PbO resulted in a 50% increase in lifetime, a 20-fold increase in quantum efficiency, and a 28-fold increase in the product of emission cross section and lifetime on the 0% PbO composition. We propose that the 800 nm absorption band relates a different bismuth center than the other absorption bands. © 2008 Optical Society of America OCIS codes: 300.2530, 140.3380.