Improving the spectral sharpness of an apodized fibre grating

Abstract

We fabricate a steep skirt fibre Bragg grating (FBG) by employing an apodized phase mask. Gaussian UV beams with different FWHM are used on the mask to derive better spectral responses. The ratio of the FBG reflection bandwidth at -0.5 to -20 dB is improved from 0.35-0.55.