Wide-Sense Nonblocking Multiplane Photonic Banyan-Type Switching Fabrics With Zero Crosstalk

Abstract

A new control algorithm for multi-plane banyantype switching fabrics has been proposed recently. It has been shown that using this algorithm such switching fabrics can be wide-sense nonblocking (WSNB) when the number of planes is lower than for the strictly nonblocking (SNB) one, and for even number of stages the WSNB switching fabric requires the same number of planes as rearrangeable one. The considered algorithm and WSNB conditions did not take into account crosstalk constraint, which is an important factor in photonic switching. This paper enhanced this algorithm to the case when the first order crosstalk in the switching fabric is not allowed. WSNB conditions for this enhanced algorithm are also derived. It is shown that the number of planes required is less than those derived earlier in other papers for WSNB multiplane banyantype switching fabrics under crosstalk constraint.

Routing Algorithms for Packet/Circuit Switching in Optical Multi-log2N Networks

“…We need also O(log 2 N) time to check the path availability for each request, the overall time complexity of all algorithms, except D algorithm [6], is just O (m·log 2 N). For the D algorithm, its complexity is as high as O(m · N 2 log 2 N) since it needs to calculate several complex matrices to achieve its low BP feature.…”

“…Danilewicz et al [6] recently proposed an novel routing algorithm for multilog 2 N networks to guarantee the nonblocking property with a reduced number of planes. The main idea of this algorithm is to select the plane that new connection will block the fewest number of future requests of all planes.…”

“…2. The multi-log 2 N networks have several attractive properties, such as good fault-tolerance capability, a small network depth and the absolute loss uniformity, which make them attractive for building the directional coupler (DC)-based optical switches to provide nano-second order switch speed [1], [4], [6], [14].…”

On the Routing Algorithms for Optical Multi-log2 N Networks

“…A multilog 2 N network consists of multiple vertically stacked planes as shown in Fig. 1, where each plane of it is just a banyan class (log 2 N ) network [1,2,3,4,5,6,7,8] illustrated in Fig. 2.…”

“…By now, several routing algorithms have been proposed for multi-log 2 N networks, such as random routing [2,3,4], packing [2], save the unused [2], etc. It is notable that the available results on routing algorithms mainly focus on the nonblocking condition analysis when a specified routing algorithm is applied [1,2,5,6,7,8]. The recent results in [2] indicate that although some routing algorithms are apparently very different, such as save the unused, packing, minimum index, etc., they actually require a same number of planes to guarantee the nonblocking property of multi-log 2 N networks.…”