  We address Anderson localization of light in disordered optical lattices
where the disorder strength varies across the transverse direction. Such
variation changes the preferred domains where formation of localized eigenmodes
is most probable, hence drastically impacting light localization properties.
Thus, step-like disorder results in formation of modes with different decay
rates at both sides of the interface, while a smoothly varying disorder yields
appearance of modes that are extended within weakly disordered domains and
rapidly fade away in strongly disordered domains.
