Abstract: The occasional coupling synchronization scheme of the active-passive decomposition (active-occasional coupling) is proposed,which consists of both synchronization and autonomous phases.In the former,the synchronization scheme is used to synchronize the drive and the response system;in the latter,small errors will lead to the separation and desynchronization of the two systems. If the synchronization phases are sufficient enough,the full synchronization will occur.The synchronization condition is discussed in theory,and the relation between the synchronization phases and the coupling strength is also investigated numerically.

Key words: spatiotemporal chaos, chaos synchronization, coupled map lattices