I received my B.Eng. degree from the University of Applied Sciences Konstanz (HTWG) in 2020, and subsequently obtained my M.Sc. degree from the Technical University of Munich (TUM) in 2022.
During my Masters thesis, I conducted research on the topic of achievable information rates for space-division multiplexed short-reach fiber-optic communication systems using direct-detection receivers, while staying with the Optical Networks Group (ONG) at University College London (UCL).
Forschung
Due to the presence of Kerr nonlinearities, a closed-form expression for the input-output relation of the fiber-optic channel cannot be derived, rendering the channel capacity indeterminate. Digital signal processing techniques, such as digital back-propagation, have been proposed as a means of mitigating nonlinear and linear fiber effects.
However, in wavelength switched networks, where receivers are only able to access their specific channel of interest and not interfering channels, only intra-channel effects, such as self-phase modulation, can be mitigated. As a result, cross-phase modulation remains a significant source of distortion in the received signal.
The nonlinear distortions that remain are typically modeled as correlated phase noise and inter-symbol interference within the channel of interest. My research focuses on developing coding schemes and receivers capable of mitigating these distortions.
Receiver scatter plots of a 16-QAM transmission with interfering channels using QPSK (leftmost plot), 16-QAM (middle plot) and Gaussian modulation (rightmost plot). Especially in the rightmost plot, nonlinear phase noise is clearly visible.
Jointly Supervised Master's Thesis in Equalization-Enhanced Phase Noise
Kurzbeschreibung: This thesis aims to investigate the modeling and/or mitigation of equalization-enhanced phase noise. The student works for Nokia and is jointly supervised by Nokia and the Institute for Communications Engineering, TUM.
Beschreibung
As an optical signal propagates through a fiber, it is distorted by chromatic dispersion. On the receiver side, the signal further experiences phase noise from the local oscillator. Compensating chromatic dispersion without consideration of the phase noise enhances the latter, which is referred to as equalization-enhanced phase noise (EEPN).
Depending on the student's interests, the thesis can focus on different aspects of EEPN, e.g., proper modeling or mitigation.
For this thesis, the student works for Nokia, but is jointly supervised and can expect close supervision from both sides. We aim to start the thesis on 7 January 2026.
Voraussetzungen
Suitable students have a basic background in optical communications and information theory. Depending on the focus of the thesis, a background in machine learning can be a plus.
Thesis in Optical Communications and Receiver Design
Beschreibung
Please reach out if you are interested in a thesis in any of my research fields. Possible areas include optical communications, particularly physical modeling and nonlinearity mitigation for single-mode fiber, and aspects of receiver design, such as receivers for channels with memory. A good background in optical communication systems and applied information theory is preferable, but the requirements generally depend on your interests. Please include a description of your interests and corresponding academic background in your application. If you have a thesis idea, I am happy to discuss your suggestions. Also, I am available to supervise external theses as long as they are in my field of expertise.
Jäger, A.; Kramer, G.: Information rates of successive interference cancellation for optical fiber. IEEE J. Sel. Areas Commun. 43 (5), 2025, 1484-1497 mehr…
Volltext (
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2024
Jäger, A.: A Tutorial on Methods for Message Passing with Continuous Variables. ICE Summer Doctoral Seminar, 2024 mehr…
Jäger, A.: Challenges and Research Trends for Fiber-Optic Communication Systems. CoC Industry Day, 2024 mehr…
Jäger, A.; Kramer, G.: Successive Interference Cancellation for Optical Fiber Using Discrete Constellations. European School of Information Theory (ESIT), 2024 mehr…
Jäger, A.; Kramer, G.: Successive interference cancellation for optical fiber using discrete constellations. European Conference on Optical Communications (ECOC), 2024 mehr…
Volltext (
DOI
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2023
Jäger, A.: Bounding the Capacity of Fiber-Optic Channels. 20th Joint Workshop on Communications and Coding (JWCC), 2023 mehr…
2022
Jäger, A.: Achievable Rates for Space-Division Multiplexed Optical Channels with Direct Detection. 6G-Life Project Work Package Workshop, 2022 mehr…