HSI lecture hall, Bldg. 30.35, Room 040, Engesserstraße 11

24. Octobre 2024, 14:00

Speaker:

Dr. Gabriele Liga is a telecommunications engineer and Assistant Professor in the Information and Communication Theory Lab (ICT lab) of the Eindhoven University of Technology (TU/e), The Netherlands, where he conducts research in the field of optical communications and teaches the MSc course “Coding for reliable and secure communications". He obtained his MSc degree in telecommunications engineering from the Politecnico of Milano, Italy, in 2011 and a PhD from the Optical Networks Group, University College London, UK in 2017 on the topic of digital techniques for high-speed optical communications. He joined the TU/e ICT lab in 2018 under a Marie Skłodowska-Curie EUROTECH research fellowship, and was later appointed Assistant Professor in the same group in 2022. Dr. Liga was recently awarded a KIT international excellence fellowship, which he is currently spending within the Communications Engineering Lab hosted by Prof. Laurent Schmalen. Overall, Dr Liga has accrued over ten years of research experience and published over 70 papers in international journals and conference proceedings. His current research interests involve: analytical modelling of the nonlinear fiber channel, digital signal processing for high-speed fibre-optic transmission, constellation shaping for fiber nonlinearity mitigation, and forward error correction for classical and quantum optical communication systems.

Abstract:
Dual-polarisation four-dimensional formats (DP-4D) can be defined as the class of 4D constellations used in optical communications whose coordinates are encoded onto the four degrees of freedom of the optical field: the two quadratures of each of the two orthogonal polarization states. The well-known polarization-multiplexed 2D (PM-2D) constellations are a subset of this quite broad class. DP-4D formats that are NOT PM-2D formats have recently received considerable attention due to their ability to outperform standard PM-2D constellations in terms of nonlinearity tolerance and achievable spectral efficiency. Examples of such formats are the 2-amplitude 8PSK (2A8PSK) and the 4D 64-polarization ring-switching (4D-64PRS) formats.
This talk will first discuss the limitations of traditional analytical models of fiber nonlinearity in correctly predicting the amount of nonlinear interference (NLI) induced by general DP-4D formats. A recent NLI model for 4D formats will then be introduced, with a focus on its mathematical formalism and the implications on the desired properties of a DP-4D format. We will then discuss the model-assisted optimization of DP-4D constellations both in terms of nonlinearity tolerance and mutual information. Finally, we will look at the performance comparison with traditional PM-2D formats and explore future research directions.