Crosstalk-Aware Counter-Propagating Core Assignment to Reduce Inter-Core Crosstalk and Capacity Wastage in Multi-Core Fiber Optical Networks

Inter-core crosstalk causes serious signal impairment in a multi-core fiber (MCF) optical network. With the extensive usage of data centers, traffic demands become increasingly asymmetric, leading to significant overall capacity wastage if the network is designed with bidirectional links. To alleviate these effects in an MCF optical network, we consider assigning the fiber cores asymmetrically, in a counter-propagating manner. This not only reduces the inter-core crosstalk between counter-propagating fiber cores significantly but also allows the flexibility of assigning different numbers of fiber cores in the opposite directions of a fiber link, thereby avoiding network capacity wastage arising from bidirectional traffic demand asymmetry. To evaluate the benefits of the proposed strategy, we consider the routing, spectrum, and core assignment (RSCA) problem for the MCF optical network. An integer linear programming (ILP) model and an auxiliary graph based heuristic algorithm are developed to optimize network spectrum resource utilization. Simulation studies show the effectiveness of the proposed crosstalk-aware core counter-propagation strategy, which can significantly outperform its counterpart, i.e., the co-propagation scheme, in terms of the total number of MCFs used and average inter-core crosstalk. In addition, the proposed RSCA heuristic algorithm is efficient to perform close to the ILP model, which can minimize the number of MCFs used and crosstalk between neighboring cores.