  The system of coupled discrete equations describing a two-component
superlattice with interlaced linear and nonlinear constituents is revisited as
a basis for investigating binary waveguide arrays, such as ribbed AlGaAs
structures, among others. Compared to the single nonlinear lattice, the
interlaced system exhibits an extra band-gap controlled by the, suitably chosen
by design, relative detuning. In more general physics settings, this system
represents a discretization scheme for the single-equation-based continuous
models in media with transversely modulated linear and nonlinear properties.
Continuous wave solutions and the associated modulational instability are fully
analytically investigated and numerically tested for focusing and defocusing
nonlinearity. The propagation dynamics and the stability of periodic modes are
also analytically investigated for the case of zero Bloch momentum. In the
band-gaps a variety of stable discrete solitary modes, dipole or otherwise,
in-phase or of staggered type are found and discussed.
