OPTICAL COMMUNICATION NETWORK

摘要

A wavelength division multiplexing ring network is constructed using a simple architecture and a fewer number of hardwares between the nodes compared with the conventional ring network. Each node is structured so that any number of multiple waves can be processed, and a fault in the network or within a node is resolved by providing a path-based protection so that switching can be performed without disrupting other nodes or even within one node. The network uses two or four lines of optical fibers, and a half of the fibers are used for communicating in a clockwise direction and a other half of the fibers are used for communicating in a counter-clockwise direction to form a logical network by optical paths contained in optical fibers so as to provide an equal number of relay nodes between two adjacent pairs of nodes throughout the network, where each node includes: multiple optical add/drop circuits; an optical path transmit end and an optical path receive end for freely selecting and outputting multiple combinations of wavelengths to be inserted in each node; and transmission lines provided between the optical add/drop circuits and the optical path transmit end, as well as between the optical add/drop circuits and the optical path receive end for transmitting any multiple waves to be processed within the node so as to establish mutual communication by transmitting processed multiple waves to other nodes. This network design enables to reduce the number of connections between the optical path transmit and receive ends, and also to reduce the number of optical signal of termination circuits.