Recently a class of scalable multi-star optical networks is proposed in [2]. In this class of networks nodes are grouped into clusters. Each cluster employs a separate pair of broadcast and select couplers. The clusters are interconnected via fiber links according to a regular topology. Self links are provided to enable connectivity among nodes in the same cluster if the cluster size is more than one. These networks can efficiently combine time and/or wavelength division with direct space division. The key design issue for these networks is the optimal conflict-free channel set assignment to the output clusters for a given cluster interconnection topology. Such conflictfree channel assignment problem has been studied for various cluster interconnection topologies