We present the forward Raman scattering study of zone-centre optical phonon
anisotropy in short-period GaAs/AlAs superlattices. Experiments were perfo
rmed on specially prepared superlattice structures having anti-reflection d
ielectric coatings and removed substrates. The experimental data are compar
ed with the angular dispersion of superlattice optical phonons calculated w
ithin the dielectric susceptibility model. We have found a good agreement b
etween the experimental data and the calculations taking into account inter
face disorder.