From optical absorption spectra and using the Judd-Ofelt theory, the phenomenological parameters, Omega(2), Omega(4) and Omega(6) of Er(DBM)(3)Phen containing methyl methacrylate (MMA) solution and solid poly(methyl methacrylate) (PMMA) matrix were obtained. The polymer chains in the sold matrix showed a significant influence on the hypersensitive transition I-4(15/2) --> H-2(11/2). The calculated radiative lifetime and stimulated emission cross section of I-4(13/2) --> I-4(15/2) transition revealed that it is promising for Er(DBM)(3)Phen containing PMMA to be used in rare earth containing polymer-based optical devices. (C) 2004 Elsevier B.V. All rights reserved.