Aktuelle Publikationen

Dezember 2020

Second Harmonic Generation in Polymer Photonic Integrated Circuits

Hauke Conradi, Norbert Keil, Martin Schell, Moritz Kleinert, Crispin Zawadzki, Ronald Freund, David de Felipe Mesquida, Martin Kresse, Björn Globisch, Lars Liebermeister, Almontaserbillah Hakmi, Madeleine Weigel

Second harmonic generation is an efficient way to create coherent radiation at wavelengths that are not accessible with standard laser sources. In this work we demonstrate second harmonic generation from 1550 nm to 775 nm in a polymer photonic...


Dezember 2020

Demonstration of Federated Learning over Edge-Computing Enabled Metro Optical Networks

Mohammad Behnam Shariati, Pooyan Safari, Angela Mitrovska, Nazila Hashemi, Johannes Fischer, Ronald Freund

We demonstrate the benefits of a federated learning framework for (re)training of global ML models over geo-distributed data sources. The demonstration is carried out on a live edge computing enabled optical networking test-bed. In this...


Dezember 2020

Predictive Resource Allocation for Automotive Applications using Interference Calculus

Daniel Fabian Külzer, Slawomir Stanczak, Renato L. G. Cavalcante, Mladen Botsov

In autonomous driving, safety-related connected applications will coexist with infotainment services. We propose a multi-cell anticipatory networking framework with interference coordination based on Interference Calculus to serve diverse QoS...


November 2020

Experimental Demonstrations of High-Capacity THz-Wireless Transmission Systems for Beyond 5G

Carlos Moises Castro Posada, Robert Elschner, Thomas Merkle, Colja Schubert, Ronald Freund

Using the concept of a “THz-Wireless Fiber Extender” it is possible to combine the flexibility of wireless networks with the high capacity of fiber-optical networks. In this article, we report on a real-time short-range demonstration of a 100...


November 2020

Dual-Band Node Architectures for C+L-Band Capacity Upgrades in Optical Metro Transport Networks

Robert Emmerich, António Eira, Nelson Costa, Pablo Wilke Berenguer, Robert Elschner, Colja Schubert, Johannes Fischer, João Pedro, Ronald Freund

To address the capacity crunch in optical metropolitan networks caused by the roll out of innovations in the context of 5G and beyond innovative approaches are required to increase the achievable throughput. Multi band systems are an interesting...


November 2020

Security Gap Investigation of Multilevel Coding in Coherent Fiber-Optical Systems

Johannes Pfeiffer, Carsten Schmidt-Langhorst, Robert Elschner, Felix Frey, Robert Emmerich, Colja Schubert, Robert F. H. Fischer

Using a coherent laboratory setup with up to 768 Gb/s data rate (64-GBd DP-64QAM), we experimentally show that multilevel coding (MLC) provides superior physical layer security (i.e. smaller security gaps) as compared to conventional...


November 2020

The socio-economic determinants of the coronavirus disease (COVID-19) pandemic

Viktor Stojkoski, Zoran Utkovski, Ljupco Kocarev, Petar Jolakoski, Dragan Tevdovski

Besides the biological and epidemiological factors, a multitude of social and economic criteria also govern the extent of the coronavirus disease spread within a population. Consequently, there is an active debate regarding the critical...


November 2020

40 GHz High-Power Photodetector Module

Tobias Beckerwerth, Patrick Runge, Martin Schell, Felix Ganzer, Jonas Gläsel

We demonstrate a fully packaged photodetector module based on surface-illuminated modified uni-traveling-carrier (MUTC) photodiode (PD) and investigate its DC and RF characteristics. It has a very a low dark current below 2 nA at the operational...


Oktober 2020

Hybrid data and model driven algorithms for angular power spectrum estimation

Renato L. G. Cavalcante, Slawomir Stanczak

We propose two algorithms that use both models and datasets to estimate angular power spectra from channel covariance matrices in massive MIMO systems. The first algorithm is an iterative fixed-point method that solves a hierarchical problem. It...


Oktober 2020

Risk Estimation of SARS-CoV-2 Transmission from Bluetooth Low Energy Measurements

Felix Sattler, Jackie Ma, Patrick Wagner, David Neumann, Markus Wenzel, Ralf Schäfer, Wojciech Samek, Klaus-Robert Müller, Thomas Wiegand

Digital contact tracing approaches based on Bluetooth low energy (BLE) have the potential to efficiently contain and delay outbreaks of infectious diseases such as the ongoing SARS-CoV- 2 pandemic. In this work we propose an approach to reliably...


September 2020

637 μW emitted terahertz power from photoconductive antennas

Robert Kohlhaas, Steffen Breuer, Lars Liebermeister, Simon Nellen, Milan Deumer, Mykhaylo P. Semtsiv, William Ted Masselink, Björn Globisch

We present photoconductive terahertz (THz) emitters based on rhodium (Rh) doped InGaAs for time-domain spectroscopy (TDS). The emitters feature a record high THz power of 637 µW. In combination with InGaAs:Rh receivers, a 6.5 THz bandwidth and a...


September 2020

Deep Learning for ECG Analysis: Benchmarks and Insights from PTB-XL

Nils Strodthoff, Wojciech Samek, Tobias Schaeffter, Patrick Wagner

This paper puts forward first benchmarking results for the PTB-XL dataset, covering a variety of tasks from different ECG statement prediction tasks over age and gender prediction to signal quality assessment. We find that convolutional neural...


September 2020

Robust and Communication-Efficient Federated Learning from Non-IID Data

Felix Sattler, Klaus-Robert Müller, Wojciech Samek, Simon Wiedemann

Federated Learning comes at the cost of a significant communication overhead during training. In this work, we propose Sparse Ternary Compression (STC), a new compression framework that is specifically designed to meet the requirements of the...


August 2020

Effect of Optical Feedback on the Wavelength Tuning in DBR Lasers

Magnus Happach, David de Felipe Mesquida, Victor Nicolai Friedhoff, Gelani Irmscher, Martin Kresse, Moritz Kleinert, Crispin Zawadzki, Walter Brinker, Martin Möhrle, Norbert Keil, Werner Hofmann, Martin Schell

Optical feedback has an impact on the tunability of lasers. We created a model of a tunable distributed Bragg reflector (DBR) laser describing the effect of optical feedback from a constant reflector distance on the wavelength tuning. Theoretical...


August 2020

Accurate and Robust Neural Networks for Face Morphing Attack Detection

Clemens Peter Seibold, Peter Eisert, Anna Hilsmann, Wojciech Samek

A morphed face image is a fusion of two face images and represents biometrics of two different subjects. Embedded in an official document, it can cause immense damage, since both subjects can claim its ownership and thus share an identity. In...


August 2020

Clustered Federated Learning: Model-Agnostic Distributed Multi-Task Optimization under Privacy Constraints

Felix Sattler, Klaus-Robert Müller, Wojciech Samek

Federated Learning (FL) is currently the most widely adopted framework for collaborative training of (deep) machine learning models under privacy constraints. However, FL yields suboptimal results if the local clients’ data distributions...


Juli 2020

Monolithically Integrated InP-Based Polarization Rotator-Splitter with Simplified Fabrication Process

Hendrik Boerma, Patrick Runge, Martin Schell, Felix Ganzer, Shahram Keyvaninia

Polarization division multiplexing doubles the transmission capacity of optical communication systems. For such systems, splitters separating the TE from the TM mode are indispensable components. We design and manufacture an integrated InP-based...


Mai 2020

PTB-XL, A Large Publicly Available Electrocardiography Dataset

Patrick Wagner, Nils Strodthoff, Ralf-Dieter Bousseljot, Dieter Kreiseler, Fatima I. Lunze, Wojciech Samek, Tobias Schaeffter

Electrocardiography (ECG) is increasingly supported by algorithms based on machine learning. We put forward PTB-XL, the to-date largest freely accessible clinical 12-lead ECG-waveform dataset comprising 21837 records from 18885 patients of 10...


April 2020

Artificial Intelligence in Dentistry: Chances and Challenges

Falk Schwendicke, Wojciech Samek, Joachim Krois

AI solutions have not by large entered routine dental practice, mainly due to (1) limited data availability, accessibility, structure and comprehensiveness, (2) lacking methodological rigor and standards in their development, (3) and practical...


April 2020

Going beyond Free Viewpoint: Creating Animatable Volumetric Video of Human Performances

Anna Hilsmann, Oliver Schreer, Peter Eisert, Ingo Feldmann, Philipp Fechteler, Wolfgang Paier, Wieland Morgenstern

We present an end-to-end pipeline for the creation of high-quality animatable volumetric video content of human performances. Going beyond the application of free-viewpoint volumetric video, we allow re-animation of an actor’s performance...



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