This paper reports the Stokes photoluminescence (PL) spectra of erbium-doped potassium niobate (KNbO3) which are prepared by synthesized method. In this work, we research the relations between PL spectra with the sintering temperature and erbium concentration. The experiments showed that H-2(1/2) --> I-4(15/2), S-4(3/2) --> I-4(15/2) and the S-4(3/2) --> I-4(13/2) emission peaks have maximum intensity at sintering temperature of 1060degreesC for the concentration of erbium, (C-Er) = 1% sample. The PL spectra is also a function of dopant concentration. It was found that the relative intensity of H-2(1/2) --> I-4(15/2), S-4(3/2) --> I-4(15/2) and the S-4(3/2) --> I-4(13/2) transitions increased as the concentration of erbium dopants increased, but then it decreased. The material characteristics were studied using X-ray diffraction, scanning electron microscopy and Raman spectrometer. (C) 2003 Elsevier B.V. All rights reserved.