Route, Modulation Format, MIMO, and Spectrum Assignment in Flex-Grid/MCF Transparent Optical Core Networks

Abstract

In this paper, we target an optimal Multiple-Input Multiple-Output Digital Signal Processing (MIMO-DSP) assignment to super-channels affected by inter-core crosstalk (ICXT) in Multi-Core Fiber (MCF)-enabled transparent optical core networks. MIMO-DSP undoes ICXT effects, but can be costly with high core density MCFs. Hence, its implementation in the network must be carefully decided. We address our objective as a joint Route, Modulation format, MIMO and Spectrum Assignment (RMMSA) problem, for which Integer Linear Programming (ILP) formulations are provided to optimally solve it in small network scenarios. Moreover, several heuristic approaches are also proposed to solve large-scale problem instances with good accuracy. Their goal is to minimize both network spectral requirements and the amount of MIMO equalized super-channels, taking a crosstalk-free Space Division Multiplexing (SDM) solution as a reference, for example, based on parallel single mode fibers (i.e., a Multi-Fiber -MF-scenario). For our evaluation, we consider several state-of-the-art MCF prototypes and different network topologies. The obtained results, with the considered MCFs, disclose that in national backbone networks, the desirable percentage of super-channels with MIMO equalization to match the performance of an equivalent crosstalk-free SDM solution ranges from 0-36%, while in continental-wide networks this range raises up to 0-56%. In addition, in the case of a non-ideal MIMO (with a 3 dB/km of crosstalk compensation), such percentages range from 0-28% and 0-45% in national and continental-wide backbone networks, respectively, experimenting a performance gap up to 12% with respect to the MF reference scenario.

Design and Assessment of FM-MCFs-Suited SDM-ROADMs With Versatile Spatial Group Configurations and Unified QoT Estimator

“…The higher the value, the lower the node complexity in terms of SDM-SSS count. In particular, given a set of homogeneous tested values (42,14,6,2), for a national backbone network with high TP the cost-efficient configuration in terms of throughput and node complexity is the one given by 6, while for a continental backbone network is 14. In any case, a conscientious node design must be accomplished by evaluating the cost-throughput tradeoff.…”

“…Nevertheless, the node design also depends on the FM-MCFs layout, more specifically, on the core count, mode count and their IM/IC XT. For example, for 6-weakly-coupled modes 7-weakly-coupled cores FM-MCFs like the prototype presented in [51], the low ICXT less than -30.2 dB/100 km, enables independent transmission in each core, i.e., the joint processing at the Rx is not mandatory, but for some XT levels ( -60 dB/km) it can be applied to improve the network performance [14]. On the other hand, for low IMXT fibers, independent transmission can be considered between the four groups illustrated in Table I., where we have two groups with 1 and two with 2.…”

“…The XT level limits the application scope to short-or long-reach communications [11]. Moreover, transparent communication, i.e., without regeneration, is only possible until the XT threshold is attained, unless Multiple-Input Multiple-Output (MIMO) is applied [12]- [14]. Various SDM fiber layouts including homogeneous and heterogeneous MCFs [15], [16] with ultra-low XT levels have been demonstrated for long-haul communications [17], [18], even fibers with high spatial channel count [19].…”

Remote Photonic THZ Generation Using an Optical Frequency Comb and Multicore Fiber

“…MCF comprising several cores in a single fiber improves the SMF transmission capacity by using spatial division multiplexing (SDM) over the different cores of the same media with improved efficiency in limited-space scenarios [8]. MCF has been indicated for elastic optical networks by using a flexible spectrum grid and DSP for inter-core crosstalk suppression [9] and we recently demonstrated its suitability for integrated wireless-optical backhaul and fronthaul provision [10]. In this work, as depicted in Fig.…”

Improving the Performance of SDM-EON Through Demand Prioritization: A Comprehensive Analysis

“…Several papers, [1], [13], [16], [18], [32], [34], [35], [41], [44]- [46], show that the order in which demands are served impacts the network fragmentation and, thus, the network capacity requirements. However, they carry out partial studies where only a handful of prioritization strategies are researched.…”