High reflectivity and narrow bandwidth fibre gratings written by single excimer pulse

The first demonstration is reported of highly reflecting fibre Bragg gratings written holographically by a single 20ns excimer laser pulse; reflection efficiencies of 65% combined with 1nm bandwidths at 1550nm have been obtained. Single-pulse gratings with FWHM bandwidths of 0.05nm (6GHz) have also been produced, to the authors' knowledge the narrowest reported to date.