Cost-efficient backup-plane architecture for single-hop WDM network

Although an AWG-based single-hop WDM network is a desirable architecture to achieve an all-optical packet network in MANs, scalability is a problem. This problem can be solved by providing optical couplers between the AWG and other nodes and collecting multiple nodes. In this case, packet collisions at couplers will significantly increase the packet network delay. Therefore, the author proposed to install an autonomic packet collision avoidance mechanism in couplers. The installation of active devices at couplers degrades the network reliability. Therefore, we need to improve the reliability by providing a backup plane when applying this method to MANs. However, simply doubling all the couplers will largely increase the CAPEX. The probability that multiple collision-avoidance mechanisms breakdown simultaneously is very small, so this paper proposes to construct the backup plane by sharing couplers among nodes accommodated in different couplers on the primary plane.