A large-scale optical switch array based on guided-wave technology using two-module-stage network architecture is proposed. Networks are derived from a generalized three-stage switch network. Two types of architecture are demonstrated. In the first, building blocks in each module are 1 n, n m nonblocking switches or n r switch that can route limited numbers of input signal. In the second, crossbar, Banyan, or four-stage wide-sense nonblocking network is used as building blocks. The interconnection is simpler than for the first type. Network architectures that use Banyan or wide-sense nonblocking network building blocks are classed as thinned-out Banyan networks.
Hideaki Okayama, Yutaka Okabe, Toru Arai, Takeshi Kamijoh, and Taiji Tsuruoka, "Two-Module Stage Optical Switch Network," J. Lightwave Technol. 18, 469- (2000)