  This paper reviews the application of coherent acoustic phonons in the form
of piezoelectrically-generated surface acoustic waves to control the response
of integrated photonic acousto-optic waveguide structures. We first address the
fundamental properties of the acoustic fields in piezoelectric materials as
well as the piezoelectric generation of surface acoustic waves using
interdigital transducers. The mechanism responsible for the interaction between
light and the acoustic modes in the photonic waveguide structures and the
modulation of the response of the devices is carefully reviewed. Next, we
discuss the most important developments in the field of integrated
acousto-optical device applications, with focus on devices built upon
three-dimensional optical waveguides. Finally, prospects for acousto-optic
device applications by use of surface acoustic waves are summarized.
