Prof. Ronald Freund Profile

Prof. Ronald Freund

at Fraunhofer HHI

SPIE Involvement:

Author

Publications (16)

Proceedings Article | 11 March 2024 Presentation + Paper

Neuromorphic reservoir for nonlinear optical signal equalization

Guillermo von Hünefeld, Binoy Chacko, Gregor Ronniger, Mahdi Kaveh, Isaac Sackey, Mahtab Aghaeipour, Peter Bienstman, Colja Schubert, Ronald Freund

Proceedings Volume 12880, 128800H (2024) https://doi.org/10.1117/12.3002627

KEYWORDS: Photonic integrated circuits, Education and training, Digital signal processing, Optical transmission, Nonlinear transmission, Neural networks, Electrooptical modeling, Network architectures, Brain-machine interfaces, Telecommunications

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Proceedings Article | 15 March 2023 Presentation + Paper

Coherent LiDAR with 2D quasi-static MEMS mirror scanning

Sarah Cwalina, Norman Laske, Shanshan Gu-Stoppel, Christoph Kottke, Volker Jungnickel, Ronald Freund

Proceedings Volume 12434, 124340K (2023) https://doi.org/10.1117/12.2647499

KEYWORDS: Mirrors, Microelectromechanical systems, LIDAR, Point clouds, Control systems, Frequency modulation, Prototyping, Infinite impulse response filters

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Proceedings Article | 15 March 2023 Presentation + Paper

18km bidirectional free-space optical link with multi-aperture antenna and DWDM SFP+ transceivers (VERTIGO project)

Nicolas Perlot, Peter Hanne, Abraham Johst, Marcel Rothe, Bill Antonio Bernhardt, Anagnostis Paraskevopoulos, Ronald Freund

Proceedings Volume 12413, 124130W (2023) https://doi.org/10.1117/12.2652245

KEYWORDS: Satellites, Laser communication terminals, Optical amplifiers, Free space optics, Field programmable gate arrays, Single mode fibers, Scintillation, Transceivers, Dense wavelength division multiplexing, Antennas

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Proceedings Article | 13 March 2023 Presentation + Paper

Purely photonic wireless link at 120 GHz carrier frequency enabled by heterodyne detection with a photoconductive antenna

Milan Deumer, Oliver Stiewe, Simon Nellen, Robert Kohlhaas, Robert Elschner, Colja Schubert, Ronald Freund, Martin Schell

Proceedings Volume 12420, 1242005 (2023) https://doi.org/10.1117/12.2649256

KEYWORDS: Receivers, Terahertz radiation, Heterodyning, Antennas, Data transmission, Wireless communications, Waveguides, PIN photodiodes

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Proceedings Article | 5 March 2021 Presentation + Paper

NRZ, DB, and DMT performance for short-reach VCSEL-based optical interconnects

Lukasz Chorchos, Nikolay Ledentsov, Oleg Makarov, Philipp Scholz, Urs Hecht, Christoph Kottke, Volker Jungnickel, Ronald Freund, Vitaly Shchukin, Vladimir Kalosha, Jarosław Turkiewicz, Friedel Gerfers

Proceedings Volume 11692, 116920D (2021) https://doi.org/10.1117/12.2578553

KEYWORDS: Optical interconnects, Modulation, Wavelength division multiplexing, Transmitters, Signal to noise ratio, Shortwaves, Vertical cavity surface emitting lasers, Receivers, Binary data

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Proceedings Article | 12 July 2019 Open Access

Tracking challenges of QKD over relay satellite

S. Sharma, N. Perlot, J. Rödiger, R. Freund

Proceedings Volume 11180, 1118062 (2019) https://doi.org/10.1117/12.2536137

KEYWORDS: Satellites, Quantum key distribution, Relays, Mirrors, Atmospheric propagation, Satellite communications, Wave propagation, Signal attenuation, Quantum communications, Turbulence

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Proceedings Article | 25 September 2017 Open Access

Benefits of time-frequency coding for quantum key distribution

J. Rödiger, N. Perlot, O. Benson, R. Freund

Proceedings Volume 10562, 105623N (2017) https://doi.org/10.1117/12.2296180

KEYWORDS: Quantum key distribution, Satellites, Time-frequency analysis, Satellite communications, Single mode fibers, Astronomical imaging, Polarization, Single photon, Optical filters, Quantum communications

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Proceedings Article | 28 January 2017 Presentation + Paper

High-speed digital-to-analog converter concepts

Christian Schmidt, Christoph Kottke, Volker Jungnickel, Ronald Freund

Proceedings Volume 10130, 101300N (2017) https://doi.org/10.1117/12.2250359

KEYWORDS: Analog electronics, Multiplexers, Telecommunications, Digital signal processing, Signal processing, Modulators, Clocks, Linear filtering, Signal to noise ratio, Multiplexing

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Proceedings Article | 29 October 2015 Paper

Preliminary results of Terabit-per-second long-range free-space optical transmission Experiment THRUST

D. Giggenbach, J. Poliak, R. Mata-Calvo, C. Fuchs, N. Perlot, R. Freund, T. Richter

Proceedings Volume 9647, 96470H (2015) https://doi.org/10.1117/12.2193902

KEYWORDS: Atmospheric optics, Receivers, Satellites, Turbulence, Dense wavelength division multiplexing, Scintillation, Free space optics, Telecommunications, Telescopes, Adaptive optics

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Proceedings Article | 4 March 2015 Paper

High-speed modulation, wavelength, and mode control in vertical-cavity surface-emitting lasers

Nikolay Ledentsov, Jörg-R. Kropp, Vitaly Shchukin, Gunther Steinle, Jarek Turkiewicz, Bo Wu, Shaofeng Qiu, Yanan Ma, Zhiyong Feng, Sven Burger, Frank Schmidt, Christoph Caspar, Ronald Freund, Kent Choquette

Proceedings Volume 9381, 93810F (2015) https://doi.org/10.1117/12.2082951

KEYWORDS: Vertical cavity surface emitting lasers, Modulation, Oxides, Optical fibers, Multimode fibers, Dielectrics, Electro optics, Dispersion, Photonic crystals, Near field

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Proceedings Article | 5 February 2013 Paper

Techniques to realize flexible optical terabit-per-second transmission systems

M. Nölle, C. Schubert, R. Freund

Proceedings Volume 8646, 864602 (2013) https://doi.org/10.1117/12.2010696

KEYWORDS: Orthogonal frequency division multiplexing, Modulation, Multiplexing, Wavelength division multiplexing, Receivers, Phase shift keying, Transmitters, Digital signal processing, Ions, Bragg cells

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Proceedings Article | 7 February 2012 Paper

Progress on single mode VCSELs for data- and tele-communications

Nikolay Ledentsov, James Lott, Jörg-R. Kropp, Vitaly Shchukin, Dieter Bimberg, Philip Moser, Gerrit Fiol, Alexey Payusov, Denis Molin, Gerard Kuyt, Adrian Amezcua, Leonid Karachinsky, Sergey Blokhin, Innokenty Novikov, Nikolay Maleev, Christoph Caspar, Ronald Freund

Proceedings Volume 8276, 82760K (2012) https://doi.org/10.1117/12.902643

KEYWORDS: Vertical cavity surface emitting lasers, Modulation, Data transmission, Multimode fibers, Reliability, Standards development, Temperature metrology, Optical interconnects, Data communications, Oxides

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Proceedings Article | 25 January 2011 Open Access

Higher-order modulation formats for spectral-efficient high-speed metro systems

R. Freund, M. Nölle, M. Seimetz, J. Hilt, J. Fischer, R. Ludwig, C. Schubert, H.-G. Bach, K.-O. Velthaus, M. Schell

Proceedings Volume 7959, 795902 (2011) https://doi.org/10.1117/12.881243

KEYWORDS: Receivers, Modulation, Phase shift keying, Transmitters, Modulators, Polarization, Tolerancing, Quadrature amplitude modulation, Digital signal processing, Field programmable gate arrays

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Proceedings Article | 11 February 2005 Paper

Design issues of 40-Gbit/s WDM systems for metro and core network application

Ronald Freund, Lutz Molle, Norbert Hanik, Andre Richter

Proceedings Volume 5625, (2005) https://doi.org/10.1117/12.581116

KEYWORDS: Wavelength division multiplexing, Modulation, Optical amplifiers, Tolerancing, Receivers, Networks, Polarization, Forward error correction, Dispersion, Chromium

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Proceedings Article | 11 February 2005 Paper

Design analysis of upgrade strategies from single- to double- and triple-wavelength-band WDM transmission

Dirk Breuer, Malte Schneiders, Sascha Vorbeck, Ronald Freund, Andre Richter

Proceedings Volume 5625, (2005) https://doi.org/10.1117/12.581119

KEYWORDS: Optical amplifiers, Raman spectroscopy, Fiber amplifiers, Wavelength division multiplexing, S band, L band, Single mode fibers, Raman scattering, Receivers, Amplifiers

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Proceedings Article | 6 August 1998 Paper

Loop experiments and simulations for the wavelength division multiplex network signal path

Bernhard Strebel, Christoph Caspar, R. Freund

Proceedings Volume 3552, (1998) https://doi.org/10.1117/12.318049

KEYWORDS: Optical amplifiers, Single mode fibers, Multiplexers, Transparency, Optical networks, Wavelength division multiplexing, Switching, Optical filters, Picosecond phenomena, Channel projecting optics

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Showing 5 of 16 publications

Conference Committee Involvement (18)

Metro and Data Center Optical Networks and Short-Reach Links

30 January 2018 | San Francisco, California, United States

Optical Metro Networks and Short-Haul Systems IX

31 January 2017 | San Francisco, California, United States

Next-Generation Optical Communication: Components, Sub-Systems, and Systems VI

31 January 2017 | San Francisco, California, United States

Optical Metro Networks and Short-Haul Systems VIII

16 February 2016 | San Francisco, California, United States

Next-Generation Optical Communication: Components, Sub-Systems, and Systems V

16 February 2016 | San Francisco, California, United States

Optical Metro Networks and Short-Haul Systems VII

10 February 2015 | San Francisco, California, United States

Next-Generation Optical Communication: Components, Sub-Systems, and Systems IV

10 February 2015 | San Francisco, California, United States

Optical Metro Networks and Short-Haul Systems VI

4 February 2014 | San Francisco, California, United States

Next-Generation Optical Communication: Components, Sub-Systems, and Systems III

4 February 2014 | San Francisco, California, United States

Next-Generation Optical Communication: Components, Sub-Systems, and Systems II

5 February 2013 | San Francisco, California, United States

Optical Metro Networks and Short-Haul Systems V

5 February 2013 | San Francisco, California, United States

Optical Metro Networks and Short-Haul Systems IV

24 January 2012 | San Francisco, California, United States

Next-Generation Optical Communication: Components, Sub-Systems, and Systems

24 January 2012 | San Francisco, California, United States

Optical Metro Networks and Short-Haul Systems III

25 January 2011 | San Francisco, California, United States

Optical Metro Networks and Short-Haul Systems II

27 January 2010 | San Francisco, California, United States

Optical Metro Networks and Short-Haul Systems

29 January 2009 | San Jose, California, United States

Optical Transmission Systems and Equipment for Networking VI

11 September 2007 | Boston, MA, United States

Optical Transmission Systems and Equipment for Networking V

2 October 2006 | Boston, Massachusetts, United States

Showing 5 of 18 Conference Committees

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