@inproceedings{47521, abstract = {{This paper experimentally investigates and interprets the e®ects of noise and non- linearity in a silicon photonic optical test structure. For the analysis di®erent optoelectronic phase noise measurement techniques are used. Our tests focuses on the performance of integrated opti- cal test structures using femtosecond pulses in the 1550nm spectral range. A primary objective is to understand the behaviour of silicon photonic waveguides that can be further employed in the implementation of an optoelectronic phase-locked loop (OEPLL) in silicon photonics technology. A comparison of our results, as well as a discussion on the di®erent optoelectronic phase noise measurement techniques are presented. Our ¯ndings provide insights that can be leveraged to optimize the design and performance of ultra-low phase noise on-chip OEPLL systems locking to mode-locked laser (MLL) signals. In the future such systems can be essential for advanced communication and sensing applications.}}, author = {{Surendranath Shroff, Vijayalakshmi and Kress, Christian and Bahmanian, Meysam and Scheytt, J. Christoph}}, booktitle = {{2023 PhotonIcs & Electromagnetics Research Symposium (PIERS), }}, location = {{Prague, Czech Republic}}, publisher = {{IEEE}}, title = {{{Analysis of Phase Noise in Waveguide-integrated Optical Test Structures in Silicon Photonics}}}, doi = {{10.1109/PIERS59004.2023.10221473}}, year = {{2023}}, } @inproceedings{42800, abstract = {{In this paper we present a new system architecture for software-defined radio / radar with optical signal distribution. The proposed architecture allows to transmit the optical carrier and an arbitrary IQ signal on the same fiber from a base station to wireless transmitters using a single laser. Furthermore, we can reuse parts, and under special conditions, also the complete optical output of the base station for the IQ return path from the wireless receiver frontends to the base station. Avoiding multiple lasers and fibers for the distribution of the carrier and arbitrary signal from the base station to the frontend, and avoiding the laser diode for the IQ return path from receiver frontends to the base station reduces the hardware effort significantly. Finally, the system architecture allows to integrate all components of the optoelectronic wireless frontend in a single chip using silicon photonics technology.}}, author = {{Kruse, Stephan and Kneuper, Pascal and Schwabe, Tobias and Meinecke, Marc-Michael and Kurz, Heiko G. and Scheytt, J. Christoph}}, location = {{Fraunhofer-Forum Berlin, Germany}}, title = {{{Distributed System Architecture for Software-Defined Radio / Radar with Optical Signal Distribution}}}, doi = {{10.23919/IRS57608.2023.10172470}}, year = {{2023}}, } @article{47126, author = {{Kruse, Stephan and Greitens, Jan C. and Schwabe, Tobias and Kneuper, Pascal and Kurz, Heiko G. and Scheytt, J. Christoph}}, journal = {{IEEE Microwave and Wireless Technology Letters }}, title = {{{A Narrowband Four-Quadrant Electro-Optical Mixer for Microwave Photonics}}}, doi = {{10.1109/LMWT.2023.3315315}}, year = {{2023}}, } @inproceedings{42804, abstract = {{This paper presents a method to model monolithically integrated photonic radar transceiver (TRX) with optical local oscillator (LO) distribution in silicon germanium (SiGe) electronic photonic integrated circuits (EPICs). The model proposed approximates the behavior of the nonlinear scattering (S)-parameters and noise figure of each building block of the TRX chipset by Laplace polynomials and hyperbolic tangent functions. The modular approach of the model allows to optimize hardware components with respect to the entire TRX system, and fault identification with reduced computational effort. The proposed method is validated using the first monolithically integrated photonic radar transceiver chipset and shows excellent agreement with the post layout simulation results and, including the photodiode (PD) bandwidth (BW) degradation, also with the measurements. }}, author = {{Kruse, Stephan and Schwabe, Tobias and Kneuper, Pascal and Meinecke, Marc-Michael and Kurz, Heiko G. and Scheytt, J. Christoph}}, location = {{Fraunhofer-Forum Berlin, Germany}}, title = {{{Nonlinear S-Parameter Behavioral Model of a Photonic Radar Transceiver Chipset for Automotive Applications}}}, doi = {{10.23919/IRS57608.2023.10172395}}, year = {{2023}}, } @inproceedings{50742, abstract = {{The nickel-based alloy Inconel 718, which is used in aerospace technology, poses a great challenge to conventional machining due to its high strain hardening and toughness. Here, the laser powder bed fusion process (LPBF) offers an alternative with potential savings if sufficiently high productivity can be achieved. Based on the parameter study carried out, starting from the SLM Solutions standard parameters for the manufacturing of components, exposure parameters could be developed to realize manufacturing with 120 μm and 150 μm layer thickness, with almost the same geometric accuracy. For this purpose, the process parameters of laser power, focus diameter, hatch distance and scan speed were varied. The negative defocusing of the laser showed a positive effect on the density of the parts, realizing densities ≥ 99.94 %, with high dimensional stability and good mechanical properties. Considering the reduced manufacturing time of up to 61 %, a significant increase in productivity was achieved.}}, author = {{Bödger, Christian and Gnaase, Stefan and Lehnert, Dennis and Tröster, Thomas}}, booktitle = {{Proceedings of the 34th Annual International Solid Freeform Fabrication Symposium – An Additive Manufacturing Conference}}, location = {{Austin}}, title = {{{Investigation of the influence of process parameters on productivity in the LPBF process for the material Inconel 718}}}, year = {{2023}}, } @article{37200, abstract = {{(1) This work answers the question of whether and to what extent there is a significant difference in mechanical properties when different additive manufacturing processes are applied to the material 1.2709. The Laser-Powder-Bed-Fusion (L-PBF) and Laser-Metal-Deposition (LMD) processes are considered, as they differ fundamentally in the way a part is manufactured. (2) Known process parameters for low-porosity parts were used to fabricate tensile strength specimens. Half of the specimens were heat-treated, and all specimens were tested for mechanical properties in a quasi-static tensile test. In addition, the material hardness was determined. (3) It was found that, firstly, heat treatment resulted in a sharp increase in mechanical properties such as hardness, elastic modulus, yield strength and ultimate strength. In addition to the increase in these properties, the elongation at break also decreases significantly after heat treatment. The choice of process, on the other hand, does not give either process a clear advantage in terms of mechanical properties but shows that it is necessary to consider the essential mechanical properties for a desired application.}}, author = {{Gnaase, Stefan and Niggemeyer, Dennis and Lehnert, Dennis and Bödger, Christian and Tröster, Thomas}}, issn = {{2073-4352}}, journal = {{Crystals}}, keywords = {{Inorganic Chemistry, Condensed Matter Physics, General Materials Science, General Chemical Engineering}}, number = {{2}}, publisher = {{MDPI AG}}, title = {{{Comparative Study of the Influence of Heat Treatment and Additive Manufacturing Process (LMD & L-PBF) on the Mechanical Properties of Specimens Manufactured from 1.2709}}}, doi = {{10.3390/cryst13020157}}, volume = {{13}}, year = {{2023}}, } @book{57594, editor = {{Decker, Claudia and Diederichs, Lara and Gefele, Katharina and Mochalova, Maria and Zierau, Cornelia}}, publisher = {{Stauffenburg Verlag}}, title = {{{Sprachbildung und interkulturelle Kompetenz im Lehramtsstudium. 10 Jahre Projekterfahrung Vielfalt stärken an der Universität und in der Bildungsregion Paderborn}}}, year = {{2023}}, } @inbook{60894, author = {{Decker, Claudia and Zierau, Cornelia}}, booktitle = {{Sprachbildung und interkulturelle Kompetenz im Lehramtsstudium. 10 Jahre Projekterfahrung Vielfalt stärken an der Universität Paderborn und in der Bildungsregion Paderborn}}, editor = {{Decker, Claudia and Diederichs, Lara and Gefele, Katharina and Mochalova, Maria and Zierau, Cornelia}}, isbn = {{978-3-95809-359-1}}, pages = {{25--38}}, title = {{{10 Jahre Vielfalt stärken: Gelingensbedingungen für ein erfolgreiches Theorie-Praxis-Projekt}}}, year = {{2023}}, } @inbook{60893, author = {{Decker, Claudia}}, booktitle = {{Sprachbildung und interkulturelle Kompetenz im Lehramtsstudium. 10 Jahre Projekterfahrung Vielfalt stärken an der Universität Paderborn und in der Bildungsregion Paderborn}}, editor = {{Decker, Claudia and Diederichs, Lara and Gefele, Katharina and Mochalova, Maria and Zierau, Cornelia}}, pages = {{15--23}}, title = {{{Steckbriefe der Teilprojekte: Vielfältige Ziele, starke Umsetzung}}}, year = {{2023}}, } @inbook{45918, author = {{Schwabl, Franziska and Daniel-Söltenfuß, Desiree}}, booktitle = {{Organisation zwischen Theorie und Praxis}}, isbn = {{9783658396893}}, issn = {{2512-1170}}, pages = {{335--349}}, publisher = {{Springer Fachmedien Wiesbaden}}, title = {{{Gelingensbedingungen gestaltungsorientierter Schulentwicklung}}}, doi = {{10.1007/978-3-658-39690-9_21}}, year = {{2023}}, } @article{61252, abstract = {{AbstractThe biexciton‐exciton emission cascade commonly used in quantum‐dot systems to generate polarization entanglement yields photons with intrinsically limited indistinguishability. In the present work, it focuses on the generation of pairs of photons with high degrees of polarization entanglement and simultaneously high indistinguishability. It achieves this goal by selectively reducing the biexciton lifetime with an optical resonator. It demonstrates that a suitably tailored circular Bragg reflector fulfills the requirements of sufficient selective Purcell enhancement of biexciton emission paired with spectrally broad photon extraction and twofold degenerate optical modes. The in‐depth theoretical study combines (i) the optimization of realistic photonic structures solving Maxwell's equations from which model parameters are extracted as input for (ii) microscopic simulations of quantum‐dot cavity excitation dynamics with full access to photon properties. It reports non‐trivial dependencies on system parameters and use the predictive power of the combined theoretical approach to determine the optimal range of Purcell enhancement that maximizes indistinguishability and entanglement to near unity values, here specifically for the telecom C‐band at 1550 nm.}}, author = {{Bauch, David and Siebert, Dustin and Jöns, Klaus D. and Förstner, Jens and Schumacher, Stefan}}, issn = {{2511-9044}}, journal = {{Advanced Quantum Technologies}}, number = {{1}}, publisher = {{Wiley}}, title = {{{On‐Demand Indistinguishable and Entangled Photons Using Tailored Cavity Designs}}}, doi = {{10.1002/qute.202300142}}, volume = {{7}}, year = {{2023}}, } @article{61266, abstract = {{This review examines the use of continuous-variable spectroscopy techniques for investigating quantum coherence and light-matter interactions in semiconductor systems with ultrafast dynamics. Special emphasis is placed on multichannel homodyne detection as a powerful tool to measure the quantum coherence and the full density matrix of a polariton system. Observations, such as coherence times that exceed the nanosecond scale obtained by monitoring the temporal decay of quantum coherence in a polariton condensate, are discussed. Proof-of-concept experiments and numerical simulations that demonstrate the enhanced resourcefulness of the produced system states for modern quantum protocols are assessed. The combination of tailored resource quantifiers and ultrafast spectroscopy techniques that have recently been demonstrated paves the way for future applications of quantum information technologies.}}, author = {{Lüders, Carolin and Barkhausen, Franziska and Pukrop, Matthias and Rozas, Elena and Sperling, Jan and Schumacher, Stefan and Aßmann, Marc}}, issn = {{2159-3930}}, journal = {{Optical Materials Express}}, number = {{11}}, publisher = {{Optica Publishing Group}}, title = {{{Continuous-variable quantum optics and resource theory for ultrafast semiconductor spectroscopy [Invited]}}}, doi = {{10.1364/ome.497006}}, volume = {{13}}, year = {{2023}}, } @article{61264, author = {{Yu, Yueyang and Dong, Chuan-Ding and Binder, Rolf and Schumacher, Stefan and Ning, Cun-Zheng}}, issn = {{1936-0851}}, journal = {{ACS Nano}}, number = {{5}}, pages = {{4230--4238}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Strain-Induced Indirect-to-Direct Bandgap Transition, Photoluminescence Enhancement, and Linewidth Reduction in Bilayer MoTe2}}}, doi = {{10.1021/acsnano.2c01665}}, volume = {{17}}, year = {{2023}}, } @article{61269, author = {{Gao, Ying and Ma, Xuekai and Zhai, Xiaokun and Xing, Chunzi and Gao, Meini and Dai, Haitao and Wu, Hao and Liu, Tong and Ren, Yuan and Wang, Xiao and Pan, Anlian and Hu, Wei and Schumacher, Stefan and Gao, Tingge}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, number = {{20}}, publisher = {{American Physical Society (APS)}}, title = {{{Single-shot spatial instability and electric control of polariton condensates at room temperature}}}, doi = {{10.1103/physrevb.108.205303}}, volume = {{108}}, year = {{2023}}, } @article{61267, abstract = {{Dynamics-induced interchain charge transfer in a polymer aggregate in stack configuration can be understood by single-oligomer polaron energy.}}, author = {{Bauch, Fabian and Dong, Chuan-Ding and Schumacher, Stefan}}, issn = {{2050-7526}}, journal = {{Journal of Materials Chemistry C}}, number = {{38}}, pages = {{12992--12998}}, publisher = {{Royal Society of Chemistry (RSC)}}, title = {{{Dynamics-induced charge transfer in semiconducting conjugated polymers}}}, doi = {{10.1039/d3tc02263c}}, volume = {{11}}, year = {{2023}}, } @inproceedings{61362, abstract = {{We study the interaction of gray tracking and DC ionic conductivity in Potassium Titanyl Phosphate (KTiOPO4, KTP) and present a novel way to reduce conductivity via a potassium nitrate treatment improving the device quality.}}, author = {{Eigner, Christof and Padberg, Laura and Quiring, Viktor and Bocchini, Adriana and Santandrea, Matteo and Gerstmann, Uwe and Schmidt, Wolf Gero and Silberhorn, Christine}}, booktitle = {{CLEO 2023}}, publisher = {{Optica Publishing Group}}, title = {{{Potassium Titanyl Phosphate Material Engineering Boosting Integrated Optical Source Performance}}}, doi = {{10.1364/cleo_at.2023.jw2a.57}}, year = {{2023}}, } @inbook{61360, author = {{Hajduk, Andreas and Zare Pour, Mohammad Amin and Paszuk, Agnieszka and Guidat, Margot and Löw, Mario and Ullmann, Fabian and Moritz, Dominik C. and Hofmann, Jan P. and Krischok, Stefan and Runge, Erich and Schmidt, Wolf Gero and Jaegermann, Wolfram and May, Matthias M. and Hannappel, Thomas}}, booktitle = {{Encyclopedia of Solid-Liquid Interfaces}}, isbn = {{9780323856706}}, publisher = {{Elsevier}}, title = {{{(Photo-)electrochemical reactions on semiconductor surfaces, part B: III-V surfaces–atomic and electronic structure}}}, doi = {{10.1016/b978-0-323-85669-0.00113-6}}, year = {{2023}}, } @inbook{46191, author = {{Alt, Christoph and Kenter, Tobias and Faghih-Naini, Sara and Faj, Jennifer and Opdenhövel, Jan-Oliver and Plessl, Christian and Aizinger, Vadym and Hönig, Jan and Köstler, Harald}}, booktitle = {{Lecture Notes in Computer Science}}, isbn = {{9783031320408}}, issn = {{0302-9743}}, publisher = {{Springer Nature Switzerland}}, title = {{{Shallow Water DG Simulations on FPGAs: Design and Comparison of a Novel Code Generation Pipeline}}}, doi = {{10.1007/978-3-031-32041-5_5}}, year = {{2023}}, } @inproceedings{46190, author = {{Opdenhövel, Jan-Oliver and Plessl, Christian and Kenter, Tobias}}, booktitle = {{Proceedings of the 13th International Symposium on Highly Efficient Accelerators and Reconfigurable Technologies (HEART)}}, publisher = {{ACM}}, title = {{{Mutation Tree Reconstruction of Tumor Cells on FPGAs Using a Bit-Level Matrix Representation}}}, doi = {{10.1145/3597031.3597050}}, year = {{2023}}, } @inproceedings{62231, abstract = {{Explainable artificial intelligence (XAI) is a rapidly growing research field that has received a lot of attention during the last few years. An important goal of the field is to use its methods to detect (social) bias and discrimination. Despite these positive intentions, aspects of XAI can be in conflict with feminist approaches and values. Therefore, our conceptual contribution brings forward both a careful assessment of current XAI methods, as well as visions for carefully doing XAI from a feminist perspective. We conclude with a discussion on the possibilities for caring XAI, and the challenges that might lie along the way.}}, author = {{State, Laura and Fahimi, Miriam}}, booktitle = {{Proceedings of the 2nd European Workshop on Algorithmic Fairness}}, publisher = {{CEUR Workshop Proceedings}}, title = {{{Careful Explanations: A Feminist Perspective on XAI}}}, year = {{2023}}, }