Constraint-based scheduling algorithm with the non-adjacency requirement for multi-flow AWG switches

Abstract

Arrayed waveguide gratings (AWGs) have been used in many optical switch architectures, but their size and signal quality are limited by the crosstalk problem. This can be tackled with wavelength constraint-based scheduling, which restricts the number of signals of the same wavelength traversing the device simultaneously.Conventional constraint-based scheduling algorithms have two limitations. First, they assume each input (output) port can only send (receive) one flow. This significantly limits the total capacity of the switch as an N × N AWG can support N flows from each port simultaneously. Second, they assume that two signals of the same wavelength have the same crosstalk effect. But in fact, the crosstalk generated by signals of non-adjacent channels is much weaker than that by adjacent channels. In this paper, we propose a new constraint-based scheduling algorithm that overcomes these two limitations and can achieve significant performance gains.