Abstract
Network traffic has been constantly increasing due to the growing popularity of various network
services. The currently deployed backbone optical networks apply wavelength division multiplexing
(WDM) techniques in single-core single-mode fibers (SMFs) to transmit the light. However, the
capacity of SMFs is limited due to the physical constraints, and new technologies are required in the
nearest future. Spectrally-spatially flexible optical networks (SS-FONs) are proposed as a scalable
solution to provide a substantial capacity increase by exploiting the spatial dimension. To this end,
suitably designed optical fibers are required where a signal is co-propagating in spatial modes, such
as, bundles of single-core single-mode fibers (SMFBs), multi-core fibers (MCFs), multi-mode fibers
(MMFs) or few-mode multi-core fibers (FM-MCFs). However, before this technology will reach
maturity, various aspects need to be addressed. The fundamental problem in the design and
operation of SS-FONs is routing, spectrum, and space allocation (RSSA) assignment. Having a set of
requests, it refers to finding a routing path and a feasible optical corridor for each of them. RSSA
problem is NP-hard as it is at least challenging as similar problems in elastic optical networks
(namely, RSA problem) or in WDM networks (i.e., RWA problem). Therefore, finding optimal solution
for larger problem instances is time consuming and the need for heuristic algorithms emerges. This
presentation focuses on various aspects of modeling and optimization of spectrally-spatially flexible
optical networks – including integer linear programming modeling, RSSA problem, network migration
planning problem and network fragmentation problem.
