The paper explores the possibility of adopting square lattice regular topologies for the implementation of wavelength-routing all-optical communication networks, i.e., communication networks in which data travel from source to destination in the optical domain, following a path that is entirely identified by the source node and the transmitted wavelength. Similar topologies were previously proposed for the implementation of interconnection networks in high-perfonnance computing systems, as well as high-speed electronic networks known under the name of Manhattan Street networks. The very limited processing capabilities presently allowed by optical technologies constrain the design of all-optical networks to the utilization of simple components. The paper shows that very simple optical components are sufficient to implement wavelength-routing all-optical networks with square grid topology.