Combined excitation-emission spectroscopy of bismuth active centers in optical fibers

For the first time, 3-dimensional luminescence spectra (luminescence intensity as a function of the excitation and emission wavelengths) have been obtained for bismuth-doped optical fibers of various compositions in a wide spectral range (450-1700 nm). The bismuth-doped fibers investigated have the following core compositions: SiO2, GeO2, Al-doped SiO2, and P-doped SiO2. The measurements are performed at room and liquid nitrogen temperatures. Based on the experimental results, the positions of the low-lying energy-levels of the IR bismuth active centers in SiO2- and GeO2-core fibers have been determined. Similarity of the energy-level schemes for the two core compositions has been revealed. (C) 2011 Optical Society of America