Application of optical multilevel transmission technique in WDM/OCDM-based core networks

In this article, we present a new scheme to improve the performance of multiservice WDM/OCDM-based core networks. The idea is based on utilizing optical multilevel transmission technique (MLTT) to mitigate the multiple access interference (MAI) effect of OCDM. In this multilevel-multiclass network, users of each class are divided into multiple groups and users of each group are allowed to transmit at a specific power level. We demonstrate that, the proposed multilevel-multiservice scheme outperforms previously introduced multiservice WDM/OCDM based networks. This is due to the interference reduction property of MLTT, and this superiority can be further enhanced by using advanced optical logic gates. The proposed scheme is a modification implemented at the data plane by upgrading the intermediate optical routers to support MLTT. In the proposed network model, data and control planes are separated and can be designed independently. However, our results reveal that a data-planeaware controlling approach, which considers the information of the data plane, outperforms a data-plane-unaware algorithm in terms of average error probability.