Metal-doped fibres for broadband emission: Fabrication with granulated oxides

The goal of the present work is testing manufacturing of metal- or transition-metal-doped fibres with the technique of granulated oxides. Optical silica fibres are drawn from preforms assembled from silica tubes filled with granulated oxides of SiO2 doped with either V2O5, Cu2O, MnO, Bi2O3 or Bi2O3–Al2O3. The produced fibres are optically excited with either a N2 laser (337 nm) or an Ar+ laser (458–514.5 nm). All the investigated ions incorporated in the silica host show a broad fluorescence in the visible range between 500 nm and 600 nm with a FWHM between 100 nm and 150 nm. Bi2O3 also shows a broad fluorescence band in the near infrared range at 1425 nm with a FWHM of about 235 nm. With the admixture of Al2O3, this fluorescence band can be shifted to 1140 nm. The measured spectra are similar to published data even if other host materials than pure silica were used. The experiment shows that fibre manufacturing with granulated oxides leads to similar spectra as MCVD or Sol–Gel technique.