Lightpath concentrators for all-optical networks

In some deployments of all-optical networks, it is necessary to concentrate the lightpaths from some fibers to fewer fibers. An N × M lightpath concentrator is an optical component for this purpose, and it concentrates the lightpaths from N incoming fibers to M outgoing fibers. In this paper, three designs of N × M lightpath concentrators are proposed. The first design is a generalization of optical crossconnects, and it requires M × M optical switches. The second design incorporates the concept of partial concentration so that it requires only m × m optical switches (where m < M) at the expense of a larger blocking probability. The switch size m can be selected to make a tradeoff between cost and performance. In the third design, it is assumed that small lightpath concentrators are available, and these concentrators are used as building blocks to construct large lightpath concentration networks.