Crosstalk-free Conjugate Networks for Optical Multicast Switching

TL;DR

This paper introduces a conjugate transformation technique that converts traditional nonblocking optical switching networks into crosstalk-free networks, enabling high-speed optical multicast switching without signal interference.

Contribution

The paper presents a novel conjugate transformation method that ensures crosstalk-free operation in optical networks by transforming route assignments, applicable to both unicast and multicast switches.

Findings

Conjugate transformation guarantees node-disjoint routes from link-disjoint ones.

Transforming existing networks yields crosstalk-free optical switches.

Applicable to both unicast and multicast optical switching networks.

Abstract

High-speed photonic switching networks can switch optical signals at the rate of several terabits per second. However, they suffer from an intrinsic crosstalk problem when two optical signals cross at the same switch element. To avoid crosstalk, active connections must be node-disjoint in the switching network. In this paper, we propose a sequence of decomposition and merge operations, called conjugate transformation, performed on each switch element to tackle this problem. The network resulting from this transformation is called conjugate network. By using the numbering-schemes of networks, we prove that if the route assignments in the original network are link-disjoint, their corresponding ones in the conjugate network would be node-disjoint. Thus, traditional nonblocking switching networks can be transformed into crosstalk-free optical switches in a routine manner. Furthermore, we show that crosstalk-free multicast switches can also be obtained from existing nonblocking multicast switches via the same conjugate transformation.