Photosensitivity in tin co-doped optical fibres

Bragg gratings have been written in SiO2:SnO2:Na2O optical fibres, where the presence of Na2O allows for higherconcentrations of SnO2. Significant refractive index modulations (up to 6.2x10^-4) have been achieved with enhanced temperature stability (no erasure up to temperatures 600 °C)