Surface acoustic wave quantum well modulators with a large number of quantum wells

Acousto-optic interactions in bulk materials and planar waveguide structures have been used to perform a number of signal processing functions. Recently, it has been reported that acousto-optical modulator performance can be enhanced by using the interaction of surface acoustic waves (SAW) with quantum well (QW) structures. However, since SAW induced piezoelectric field decays non-uniformly with depth, strong SAW effects can only be obtained at the top surface with small number of quantum wells (e.g. 5 QWs). In this paper we show that improved SAW electroabsorptive and electro-optic modulators can be obtained using a thick QW region, which contains a 25 period 100Å-100Å Al_0.3Ga_0.7As-GaAs QW structure