Continuous tuning of radiation frequency in fibre and waveguide lasers by a controllable Bragg grating

A method for fast radiation wavelength tuning is proposed for a single-frequency fibre laser. A diffraction grating written on a waveguide electrooptical modulator serves as the mirror of the external cavity and as the selector. The voltage supplied to the grating electrodes shifts the reflection band of the grating and hence tunes the emitted radiation range. The radiation frequency tuning within the grating reflection band is carried out by using an intracavity waveguide electrooptical cell. The spectral characteristics of laser radiation are calculated. It is shown that the tuning range of such a laser achieves 0.2 nm for a control voltage up to 5 V, the switching time being shorter than 0.7 ns.