Motivated by recent experimental observations of anomalous
diffraction in linear waveguide array, we propose a novel model
governing the propagation of an optical beam in a diffraction managed
nonlinear waveguide array. This model supports discrete
spatial solitons whose beam width and peak amplitude evolve periodically.
A nonlocal integral equation governing the slow evolution of the soliton
amplitude is derived and its stationary soliton solutions are obtained.
Ref. M.J. Ablowitz and Z. Musslimani, PRL 87, 254102 (2001).