Inscription of narrow-band fibre Bragg gratings with 264 nm femtosecond pulses

Abstract We fabricated narrow-band fibre Bragg gratings (FBGs) in photosensitive Ge/B codoped fibre by a scanning mask technique with high-intensity (30–60 GW/cm 2 ) 264 nm 220 fs laser pulses. Comparing with recently reported inscription using 800 nm pulses and same scanning approach, our gratings demonstrate a smaller linewidth down to 0.2 nm and much higher grating strength at shorter length. In addition, the obtained results demonstrate the absence of significant off-band losses.