The log_2{N-1} Optical Switching Fabrics

In this article, we introduce a new space-division optical switching fabric architecture based on baseline switching networks. The new structure is built from optical switching elements (OSE) 2 × 2, 3 × 3, 2 × 3, and 3 × 2. The new structure is called the log₂ N-1 switching network and consists of fewer numbers of active and passive optical elements than traditional baseline switching networks composed of symmetrical OSEs. In the paper, we investigate space-division multiplane strict-sense and rearrangeable log₂ N-1 nonblocking switching networks and compare these with space-division multiplane baseline switching networks. The new structure has lower cost than other architectures for strict-sense nonblocking (SSNB) conditions and for rearrangeable (RNB) networks with odd number of stages. For RNB networks, when the number of stages is even, the cost of the multiplane log₂ N-1 optical switching network is equal to or higher than traditional networks.