Acousto-optic tunable filters for wavelength division multiplexed optical fibre systems

The three important device elements of a channel selecting lithium niobate acousto-optic tunable filter (operating at both 1.3 mu m and 1.55 mu m) are the optical waveguide, the surface acoustic wave (SAW) transducer and the waveguide polariser. The design and fabrication of these elements to achieve low loss, broad tunability and narrow passband are reported and the performance of a channel selecting filter when fully packaged with fibre tails and components for temperature control is described. >