N-Stage Planar Optical Permutation Network

1. Introduction: Permutation networks have played an essential role in telephone switching systems, in computer interconnection networks, and in processing hardware. Modern large circuit switching networks are constructed from several smaller basic permutation networks, where each N X N permutation network can perform any required permutation of the N inputs. In circuit switching, incoming information on any of the N input lines can be directed to any one of the N output lines. The study of permutation networks deals fundamentally with the design and analysis of crosspoint patterns.