Simple technique for apodising chirped and unchirped fibre Bragg gratings

For the first time, a simple technique is reported for apodising chirped or unchirped gratings of arbitrary length. Also reported for the first time is the fabrication and measurement of unapodised and apodised 100 mm long, step-chirped fibre gratings with a dispersion parameter of ~1.6 ns-nm^-1 and a bandwidth of up to 0.75 nm. It is shown that long chirped gratings may be fabricated at predetermined wavelengths in standard telecommunications fibre for dispersion compensation