An integrated-optic Fourier processor consisting of an acoustooptic (AO) deflector and graded-index Fresnel lenses in an As <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> waveguide on a SiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> /Si substrate is proposed and the prototype device is demonstrated. For the interdigital transducer (IDT) for surface acoustic wave excitation, a two-stage array of uniform-period IDT and a chirped IDT using a ZnO piezoelectric film are adopted. High efficielicy and low drive power, as well as wide bandwidth of one octave in the device with a chirped IDT, have been obtained and the Fourier transformation function has been confirmed.