An optical switch fabric with an input stage, an output stage, and a center stage coupled in a cascaded manner. The center stage includes (1) a minimum number of center switches greater than one that cause the optical switch fabric to be strict-sense nonblocking and (2) at least one additional center...http://www.google.com/patents/US6882766?utm_source=gb-gplus-sharePatent US6882766 - Optical switch fabric with redundancy
