The fluorescence properties of oxyfluoride glass ceramics containing nanosized LaF3 crystals with different ErF3 doping level were investigated. The spectroscopy analysis indicated that a dominant fraction of ErF3 had been incorporated into the crystal phase. Broad 1.5 mu m emission spectra with full width at half maximum (FWHM) value ranging from about 40-100 nm were obtained, which increased accordingly with ErF3 doping level. Noteworthily, intense green and red upconversion emissions from samples with high ErF3 doping level were observed when excited even with a 30 mW diode laser at 976 nm. An overall increment of the upconversion emissions intensity, and, a relative increase in intensity of the red emission with respect to that of the green one were also identified with increasing ErF3 concentration. The possible upconversion mechanisms were proposed. (c) 2006 Elsevier B.V. All rights reserved.