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

Single-hop wavelength division multiplexing (WDM) networks based on a central arrayed waveguide grating (AWG) have attracted a great deal of attention as a solution for metropolitan area network 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 connecting to the AWG. In this case, however, packet collisions at the couplers will seriously increase the packet network 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 network cost dramatically.