Luminescence from bismuth-germanate glasses and its manipulation through oxidants

Abstract

We report on the luminescence properties of bismuth-germanate glasses in which the speciation of bismuth is controlled via addition of CeO2 as an oxidant. A glass system with the composition (70.5-x)GeO2 - 24.5Bi2O3 - 5WO3: xCeO2, with x = 0...2.0, is analyzed in terms of optical properties and redox states of bismuth and cerium. We show that optical transmission and luminescence in the visible to near-infrared (NIR) spectral range can be adjusted by the ratio of bismuth and cerium. Specifically, ultrabroad NIR luminescence spanning the range of 1000 - 1600 nm can be obtained for x ≤ 0.1. This is of particular interest for application of this type of glass in fiber-optical amplifiers where no additional dopants would be required. © 2012 Optical Society of America.