Recent publications

August 2023

1x4 Vertical Power Splitter/Combiner: A Basic Building Block for Complex 3D Waveguide Routing Networks

Madeleine Weigel, Norbert Keil, Martin Schell, Moritz Kleinert, Crispin Zawadzki, D. De Felipe, Martin Kresse, Tianwen Qian, Jakob Reck, Klara Mihov, Jan H. Bach, Philipp Winklhofer

A novel polymer-based 1x4 vertical multimode interference (MMI) coupler for 3D photonics is presented. It connects four vertically stacked waveguide layers with a spacing of 21.6 µm. The functionality is demonstrated on a fabricated device.

July 2023

Optimization of Ultra-Broadband Optical Wavelength Conversion in Nonlinear Multi-Modal Silicon-On-Insulator Waveguides

Isaac Sackey, Norbert Hanik, Colja Schubert, Ronald Freund, Lars Zimmermann, Gregor Ronniger, Tasnad Kernetzky, Yizhao Jia, Ulrike Höfler

Ultra-broadband wavelength conversion is identified as one of the key issues in future high capacity, flexible optical networks. In this contribution, methods to optimize the design of a multi-modal high-nonlinear SOI waveguide to achieve...

July 2023

Automatic Reconstruction of Semantic 3D Models from 2D Floor Plans

Aleixo Cambeiro Barreiro, Peter Eisert, Anna Hilsmann, Mariusz Trzeciakiewicz

Digitalization of existing buildings and the creation of 3D BIM models is crucial for many tasks. Of particular importance are floor plans, which contain information about building layouts and are vital for construction, maintenance or...

July 2023

Eight-channel SiNx microring–resonator based photonic biosensor for label-free fluid analysis in the optical C-band

Jakob Reck, Norbert Keil, Martin Schell, Moritz Kleinert, Crispin Zawadzki, David de Felipe Mesquida, Martin Kresse, Hauke Conradi, Tianwen Qian, Cafercan Yilmaz, Madeleine Weigel, Klara Mihov, Christina Hoffmann, Peter Hoffmann, Vera Froese, Ulrich Kertzscher, Kristina Mykhailiuk, Julia Michaelis, Wilfired Weigel, Sören Scholand, Hans-Jürgen Heupke

A lab-on-a-chip multichannel sensing platform for biomedical analysis based on optical silicon nitride (SiNx) mi- croring-resonators (MRR) was established. The resonators were surface functionalized and finally combined with a microfluidic...

June 2023

Accurate human body reconstruction for volumetric video

Decai Chen, Oliver Schreer, Peter Eisert, Ingo Feldmann, Markus Worchel

In this work, we enhance a professional end-to-end volumetric video production pipeline to achieve high-fidelity human body reconstruction using only passive cameras.We introduce and optimize deep learning based multi-view stereo networks for...

June 2023

Dynamic Multi-View Scene Reconstruction Using Neural Implicit Surface

Decai Chen, Oliver Schreer, Peter Eisert, Ingo Feldmann, Haofei Lu

In this paper, we propose a template-free method to reconstruct surface geometry and appearance using neural implicit representations from multi-view videos. We leverage topology-aware deformation and the signed distance field to learn complex...

June 2023

Preserving Memories of Contemporary Witnesses Using Volumetric Video

Volumetric Video is a novel technology that allows the creation of dynamic 3D models of persons, which can then be integrated in any 3D environment. It is authentic and much more realistic and therefore ideal for the transfer of emotions, facial expressions and gestures, which is highly relevant in the context of preservation of contemporary witnesses and survivors of the Holocaust. Fraunhofer HHI is working on two projects in this cultural heritage. A VR documentary about the last Ger! man survivor of the Holocaust Ernst Grube has been produced together with UFA GmbH. A second project is with Dr. Eva Umlauf, the youngest Jewish survivor in the concentration camp in Auschwitz.

Oliver Schreer, Peter Eisert, Ingo Feldmann, Anna Hilsmann, Sylvain Renault, Marcus Zepp, Wieland Morgenstern, Rodrigo Mauricio Diaz Fernandez, Markus Worchel

June 2023

Increasing the power and spectral efficiencies of an OFDM-based VLC system through multi-objective optimization

Wesley Da Silva Costa, Volker Jungnickel, Ronald Freund, Anagnostis Paraskevopoulos, Malte Hinrichs, Higor Camporez, Maria Pontes, Marcelo Segatto, Helder Rocha, Jair Silva

In order to minimize power usage and maximize spectral efficiency in visible light communication (VLC), we use a multi-objective optimization algorithm and compare DC-biased optical OFDM (DCO-OFDM) with constant envelope OFDM (CE-OFDM)...

June 2023

Optimizing Explanations by Network Canonization and Hyperparameter Search

Frederick Pahde, Wojciech Samek, Alexander Binder, Sebastian Lapuschkin, Galip Ümit Yolcu

Rule-based and modified backpropagation XAI methods struggle with innovative layer building blocks and implementation-invariance issues. 

In this work we propose canonizations for popular deep neural network architectures and...

June 2023

Experimental Demonstration of Optical Modulation Format Identification Using SOI-based Photonic Reservoir

Guillermo von Hünefeld, Colja Schubert, Ronald Freund, Johannes Fischer, Isaac Sackey, Gregor Ronniger, Pooyan Safari, Md Mahasin Khan, Rijil Thomas, Enes Seker, Stephan Suckow, Max Lemme, David Stahl

We experimentally show modulation format identification in the optical domain using Silicon-on-Insulator-based Photonic-Integrated-Circuit (PIC) reservoir. Identification of 32 GBd single-polarization signals of 4QAM, 16QAM, 32QAM and 64QAM is...

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