Chirped fibre gratings produced by tilting the fibre

Abstract
A new and simple method for writing chirped fibre gratings is presented. It involves the use of a phase mask combined with a spherical lens and requires a controlled tilt between the fibre and the phase mask surface. A chirped grating has been written in a hydrogen-loaded standard telecommunication fibre. A peak reflectivity of 96% and a bandwidth of 6.0 nm have been achieved. This technique allows the production of a large range of chirp magnitudes.