We investigate the interplay of Bloch oscillations and Anderson localization
in optics. Gradual washing out of Bloch oscillations and the formation of
nearly stationary averaged intensity distributions, which are symmetric for
narrow and strongly asymmetric for broad input excitations, are observed
experimentally in laser-written waveguide arrays. At large disorder levels
Bloch oscillations are completely destroyed and both narrow and wide
excitations lead to symmetric stationary averaged intensity distributions with
exponentially decaying tails.Comment: 3 pages, 6 figures, to appear in Optics Letter