| 摘要 |
A dilated N x N optical cross-connect switch suitable for large N exhibits good efficiency (element count) without a significant increase in and reduced sma ll depth (low loss) and crosstalk. The present arrangement consists of six levels of binary trees of 1x2 and 2x1 elements. The first two levels form the input stage, the thir d and fourth levels form the center stage, and the fifth and sixth levels form the output stage. In each of the input, center, and output stages, the odd number level is formed as a binary tree of 1x2 elements and the even numbered level is formed as a binary tree of 2x 1 elements. Each stage is formed by directly joining together the 1x2 element binary tree with the 2x1 element binary tree. In one embodiment, depth is substantially reduced by using a symmetric arrangement of one or more 2x2 elements located in the vicinity of each junction between adjacent stages. The arrangement also features reduced depth obtained by a Clos type construction.
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