A novel large-scale AWG-based single-hop WDM network with collision avoidance

Single-hop WDM networks based on a central AWG have attracted a great deal of attention as a solution for MAN applications because they can achieve high throughput with reduced cost due to the periodic wavelength-routing property of the AWG. Unfortunately, scalability is a significant problem in an AWG-based single-hop WDM network because the number of transceivers required at each node is equal to the total number of nodes. This problem can be solved by providing optical couplers between the AWG and the nodes and by aggregating multiple nodes before connection to the AWG. In this case, however, packet collisions at the couplers will seriously increase the packet delay. Therefore, we propose a novel AWG-based single-hop WDM network in which an autonomic collision avoidance mechanism is introduced in the couplers. We derive the optimum number of couplers for this architecture. Through numerical study, we clarify that the proposed network architecture can reduce the total required number of transceivers dramatically.