Distance-adaptive modulation for space-division multiplexed optical systems

Abstract

The evolution of the demand for inter- and intra-datacenter data traffic requires solutions of fiber-optic communication systems that are energy efficient, maintaining the trend of reducing the cost per transmitted bit. Space-Division Multiplexing (SDM) is a promising solution, if not the only one, capable of meeting these requirements. In this technique, distinct signals are simultaneously transmitted in different spaces using bundles of single-mode optical fibers in a cable, multi-core fibers or multimode fibers. As a long-term option, spatial multiplexing with channel coupling is of particular interest, whether in multicore fibers with coupled cores or with multimode fibers. In these systems, Multiple-In Multiple-Out (MIMO) digital signal processing techniques are required, which, however, increases the computational complexity of the transceivers. As in today's flexible optical systems, future SDM systems must adapt to the reach of the transmission link. For this, channel estimation techniques and decision making are required to adapt the modulation formats and the digital signal processing algorithms in the transmitter and receiver. In this scenario, this thesis aims to investigate channel estimation techniques in SDM systems with modal coupling, as well as the adaptation of the underlying modulation and digital signal processing algorithms. We will also evaluate the interest in the dissemination of physical layer parameters to upper layers, aiming at a future integration of the transceiver to the control plane. The work will include computational simulations and possibly experimental measurements in partner laboratories. (AU)