Bragg gratings written in multimode borosilicate fibres using ultrafast infrared radiation and phase mask

Inscription of Bragg grating structures is reported for the first time in multimode borosilicate fibres using femtosecond pulse duration 800 nm infrared radiation and a phase mask. Thermal annealing of the gratings up to 700°C reveals a behaviour similar to type I-IR gratings made in silica fibre with ultrafast infrared radiation.