Silica-based glasses doped with Sm2+ have been prepared by using vapor-phase axial deposition method under a reducing atmosphere. The fluorescence spectra reveal that the reduction of Sm3+ to Sm2+ ions is accomplished in the silica glass codoped with Al2O3,while the Sm2+ ions are not incorporated into the silica glass without Al2O3 The effects of Al2O3 codopant on the coordination change around divalent rare-earth ions are discussed according to our previous studies of (EU)-E-151 Mossbauer effects. It is assumed that the divalent rare-earth ions are preferentially coordinated by Al polyhedra, resulting in the stability of the lower valence state of the rare-earth ions. Persistent spectral hole burning is also demonstrated at room temperature for the F-7(0)-D-5(0) transition of Sm2+ in the aluminosilicate glass fiber. A hole width of 6 cm(-1) is much narrower than the inhomogeneous width of 100 cm(-1), leading to the ratio of inhomogeneous-to-homogeneous width of similar to 40. (C) 2000 Published by Elsevier Science B.V. All rights reserved.