  We report the first experimental evidence of a successful synchronization of
spatiotemporal chaos. The experiments were performed on two unidirectionally
coupled, nonlinear-optical systems of single-feedback type. The synchronization
was investigated for different degrees of complexity of the spontaneous
structures. In all cases, the cross-correlation between the two system states
was found to increase with the strength of the coupling. Numerical simulations
yield comparable results and throw a light on the role of spatial
inhomogeneities, which hamper a perfect synchronization.
