Abstract: The invention relates to a tuneable AWG device for multiplexing and demultiplexing signals and to a method for tuning said device. The inventive device is an integrated-optic device which enables a signal made up of a plurality of signals multiplexed by wavelength division to be injected through an input port such as to obtain, at the output, a demultiplexed signal with each component exiting via a different port. If the multiplexed signal is changed to another input port, the demultiplexed signals appear at different ports, but always according to a pre-determined relationship. The invention makes it possible to tune the AWG device by using stationary acoustic waves such that the acoustically excited optical guides are excited by a linear acoustic wave.