Title: “Nonlinear Fourier transform for dual-polarization optical communication systems”
Supervisors:
Principal supervisor: Assoc. Prof. Darko Zibar, DTU Fotonik
Evaluation Board:
Professor Jesper Mørk, DTU Fotonik
Professor Sergei K. Turitsyn, Director of the Aston Institute of Photonic Technologies, Aston University, UK
Assistent Professor Sander Wahls, Delft University of Technology, The Netherlands
Master of the Ceremony:
Assoc. Prof. Lars Hagedorn Frandsen, DTU Fotonik
Abstract:
New services and applications are causing an exponential increase in the Internet traffic. In a few years, the current fiber-optic communication system infrastructure will not be able to meet this demand because fiber nonlinearity dramatically limits the information transmission rate. Eigenvalue communication is considered an emerging paradigm in fiber-optic communications that could potentially overcome these limitations. It relies on a mathematical technique called "nonlinear Fourier transforms (NFT)" to exploit the "hidden" linearity of the Nonlinear Schrödinger equation as the master model for signal propagation in an optical fiber. One of the rapidly evolving NFT-based communication techniques is called nonlinear frequency division multiplexing (NFDM). Being still in its infancy, NFDM systems still have some practical limitations, among which the lack of polarization division multiplexing.
This thesis addresses this problem by introducing the novel concept of dual-polarization NFDM. First, the theoretical tools that define the NFT for the Manakov system, which describes the evolution of a dual-polarization signal in a single-mode fiber, are presented. Using these tools the discrete dual-polarization NFDM system is defined, and it is experimentally validated for the first time. It was possible to achieve a transmission of up to 373.5 km with bit error rate smaller than the hard-decision forward error correction threshold.