Compensation of imperfect phase mask with moving fibre-scanning beam technique for production of fibre gratings

The authors experimentally demonstrate that the moving fibre-scanning beam technique is able to compensate for imperfections in a phase mask and thus improve the quality of the resulting fibre gratings. A 10 cm long `uniform´ phase mask which normally produces gratings with a 0.23 nm uncontrolled chirp has been corrected with their new writing technique to produce narrow-band gratings with a 0.10 nm bandwidth