The concept of a light-tree is introduced in a wavelength-routed optical network. A light-tree is a point-to-multipoint generalization of a lightpath. A lightpath is a point-to-point all-optical wavelength channel connecting a transmitter at a source node to a receiver at a destination node. Lightpath communication can significantly reduce the number of hops (or lightpaths) a packet has to traverse; and this reduction can, in turn, significantly improve the networkâ€™s throughput. We extend the lightpath concept by incorporating an optical multicasting capability at the routing nodes in order to increase the logical connectivity of the network and further decrease its hop distance.