A light emitting Si-doped glass (Si-DG) film was fabricated using the ion beam sputter-deposition (IBSD) technique. Although the photoluminescence (PL) intensity increased with increasing annealing temperature up to approximately 900 degreesC, it often decreased above the critical temperature. According to high-resolution transmission electron microscope (TEM) observations, Si crystallites with a diameter of approximately 3 nm were found in the film after the heat treatment, indicating that the formation of Si crystallites is closely related to the luminescence intensity. The luminescent Si-DG film showed extremely broad PL spectra, the full width at half-maximum (FWHM) typically being approximately 1 eV. To obtain a much sharper bandwidth for light emission, the Si-DG him was sandwiched by a metal (Ag) film and a dielectric multilayered reflector. The FWHM value of the PL spectrum was reduced to approximately 0.1 eV after fabricating the resonates using a 20-paired CeO2/Si-DG multilayered reflector.