Planar and channel waveguides based on 'Er POT.3+' doped 'SiO IND.2'-'Ta IND.2''O IND.5': structural and optical properties - Ferrari, J. L.; Lima, K. O.; Maia, L. J. Q.; Gomes, A. S. L.; Ribeiro, S. J. L.; Gonçalves, Rogéria Rocha (Brazilian Meeting on Inorganic Chemistry (BMIC), 2008)