@inproceedings{46426,
  abstract     = {{One of the main challenges for next generation automotive radars is the improvement of angular resolution to a sub-degree level. In this context, wide aperture automotive radars of 1m length or more and resolution close to 0.1° in azimuth and 0.5° in elevation could be beneficial. To enable coherent processing of arrays with such large aperture, prior (i.e offline) and online calibration are necessary: channel imbalances (gains and phases) and three dimensional coordinates of transmit and receive elements need to be determined. We propose a calibration strategy based on alternating steps between the two subtasks of i) channel imbalance estimation with ‘known’ array positions, by applying a singular value decomposition to the resulting tensor calculus problem; and ii) antenna position estimation with ’known’ channel imbalances, by numerically maximizing the Bayesian posterior probability; in both cases operating on range/Doppler snapshots of disjoint targets (with potentially unknown locations). Simulation studies based on the parameters of a MIMO 8x6 linear sparse array show promising results as long as the initial position errors do not exceed half a wavelength (2mm), beyond which we observe strong effects of ambiguity. Experimental results with real measurements show that after calibration in laboratory conditions, our MIMO 8x6 demonstrator with 50cm aperture is able to resolve two targets at the same range with angular separation at least as close as 0.4°.}},
  author       = {{Greiff, Christian  and Mateos-Núñez, David and Simoni, Renato and González-Huici, Maria and Kruse, Stephan and Scheytt, J. Christoph and Kolk, Karl and Höller, Christian and Kurz, Heiko Gustav and Meinecke, Marc-Michael and Gisder, Thomas}},
  booktitle    = {{2023 24th International Radar Symposium (IRS)}},
  location     = {{Berlin, Germany}},
  publisher    = {{IEEE}},
  title        = {{{Calibration of Large Coherent MIMO Radar Arrays: Channel Imbalances and 3D Antenna Positions}}},
  doi          = {{10.23919/IRS57608.2023.10172475}},
  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}},
}

@inproceedings{47124,
  author       = {{Kruse, Stephan and Meinecke, Marc-Michael and Kneuper, Pascal and Schwabe, Tobias and Kurz, Heiko G. and Scheytt, J. Christoph}},
  booktitle    = {{2023 20th European Radar Conference (EuRAD)}},
  location     = {{Berlin}},
  title        = {{{Analysis and Simulation of a Coherent FMCW Lidar-Photonic Radar Combined Sensor System for Large Aperture Phased Array MIMO}}},
  doi          = {{10.23919/EuRAD58043.2023.10289439}},
  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{47064,
  author       = {{Iftekhar, Mohammed and Nagaraju, Harshan and Kneuper, Pascal and Sadiye, Babak and Müller, Wolfgang and Scheytt, J. Christoph}},
  booktitle    = {{BCICTS 2023 IEEE BiCMOS and Compound Semiconductor Integrated Circuits and Technology Symposium}},
  location     = {{MONTEREY, CALIFORNIA, USA}},
  title        = {{{A 28-Gb/s 27.2 mW NRZ Full-Rate Bang-Bang Clock and Data Recovery in 22 nm FD-SOI CMOS Technology }}},
  year         = {{2023}},
}

@inproceedings{29767,
  author       = {{Abughannam, Saed and Scheytt, J. Christoph}},
  booktitle    = {{International Symposium on Circuits and Systems (ISCAS 2022)}},
  publisher    = {{IEEE Xplore}},
  title        = {{{Low-Power Low-Data-Rate Wireless PPM Receiver Based on 13-Bits Barker Coded SAW Correlator with Scalable Data-Rate and Sensitivity}}},
  year         = {{2022}},
}

@article{30012,
  abstract     = {{The growing demand for bandwidth and energy efficiency requires new solutions for signal detection and processing. We demonstrate a concept for high-bandwidth signal detection with low-speed photodetectors and electronics. The method is based on the parallel optical sampling of a high-bandwidth signal with sinc-pulse sequences provided by a Mach-Zehnder modulator. For the electronic detection and processing this parallel sampling enables to divide the high-bandwidth optical signal with the bandwidth B into N electrical signals with the baseband bandwidth of B/(2N) . In proof-of-concept experiments with N=3 , we present the detection of 24 GHz optical signals by detectors with a bandwidth of only 4 GHz. For ideal components, the sampling and bandwidth down-conversion does not add an excess error to the signals and even for the non-ideal components of our proof-of-concept setup, it is below 1%. Thus, the rms error for the measurement of the 24 GHz signal was reduced by a factor of about 3.4 and the effective number of bits were increased by 1.8.}},
  author       = {{Meier, Janosch and Singh, Karanveer and Misra, Arijit and Preussler, Stefan and Scheytt, Christoph and Schneider, Thomas}},
  issn         = {{1943-0655 }},
  journal      = {{IEEE Photonics Journal}},
  title        = {{{High-Bandwidth Arbitrary Signal Detection Using Low-Speed Electronics}}},
  doi          = {{10.1109/JPHOT.2022.3149389}},
  volume       = {{14}},
  year         = {{2022}},
}

@article{34237,
  author       = {{Kruse, Stephan and Gudyriev, Sergiy and Kneuper, Pascal and Schwabe, Tobias and Meinecke, Marc-Michael and Kurz, Heiko G. and Scheytt, J. Christoph}},
  issn         = {{1531-1309}},
  journal      = {{IEEE Microwave and Wireless Components Letters}},
  number       = {{12}},
  pages        = {{1447--1450}},
  publisher    = {{Institute of Electrical and Electronics Engineers (IEEE)}},
  title        = {{{Silicon Photonic Radar Receiver IC for mm-Wave Large Aperture MIMO Radar Using Optical Clock Distribution}}},
  doi          = {{10.1109/lmwc.2022.3186432}},
  volume       = {{32}},
  year         = {{2022}},
}

@inproceedings{34238,
  abstract     = {{<jats:p>A monolithically integrated electronic-photonic Mach-Zehnder modulator is presented, incorporating electronic linear drivers along photonic components. An electro-optical 3 dB &amp; 6 dB bandwidth of 24 GHz and 34 GHz respectively was measured. The on-chip drivers decrease the V<jats:italic>
      <jats:sub>π</jats:sub>
    </jats:italic> by a factor of 10.</jats:p>}},
  author       = {{Kress, Christian and Schwabe, Tobias and Rhee, Hanjo and Kerman, Sarp and Scheytt, J. Christoph}},
  booktitle    = {{Optica Advanced Photonics Congress 2022}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Broadband Mach-Zehnder Modulator with Linear Driver in Electronic-Photonic Co-Integrated Platform}}},
  doi          = {{10.1364/iprsn.2022.im4c.1}},
  year         = {{2022}},
}

@article{34230,
  abstract     = {{We present the design and experimental characterization of a silicon nitride pulse interleaver based on coupled resonator optical waveguide filters. In order to achieve a targeted free spectral range of 1.44 THz, which is large given the reduced optical confinement of the silicon nitride platform, individual ring resonators are designed with tapered waveguides. Its application to time-interleaved photonically-assisted ADCs is analyzed by combining experimental characterization of the photonic integrated circuit with a comprehensive model of the entire ADC. The impact of fundamental signal distortion and noise sources affecting the converter is investigated and suitable equalization techniques at the digital signal processing level are evaluated. The novel application of a simple but powerful equalization filter in the DSP domain allows for a significant improvement of the digitized signal SNR. An ENOB of 5 over a 75 GHz bandwidth (150 GS/s) and an ENOB of 4.3 over a 100 GHz bandwidth (200 GS/s) are expected to be achievable with compact and off-the-shelf single-section semiconductor mode locked lasers, that can be further improved with lower noise light sources.}},
  author       = {{Zazzi, Andrea and Müller, Juliana and Ghannam, Ibrahim and Battermann, Moritz and Rajeswari, Gayatri Vasudevan and Weizel, Maxim and Scheytt, J. Christoph and Witzens, Jeremy}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  number       = {{3}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Wideband SiN pulse interleaver for optically-enabled analog-to-digital conversion: a device-to-system analysis with cyclic equalization}}},
  doi          = {{10.1364/oe.441406}},
  volume       = {{30}},
  year         = {{2022}},
}

@article{34239,
  author       = {{Bahmanian, Meysam and Scheytt, J. Christoph}},
  issn         = {{0018-9480}},
  journal      = {{IEEE Transactions on Microwave Theory and Techniques}},
  number       = {{10}},
  pages        = {{4422--4435}},
  publisher    = {{Institute of Electrical and Electronics Engineers (IEEE)}},
  title        = {{{Noise Processes and Nonlinear Mechanisms in Optoelectronic Phase-Locked Loop Using a Balanced Optical Microwave Phase Detector}}},
  doi          = {{10.1109/tmtt.2022.3197621}},
  volume       = {{70}},
  year         = {{2022}},
}

@misc{48628,
  author       = {{Kruse, Stephan and Scheytt, J. Christoph}},
  title        = {{{Elektrooptischer Mischer}}},
  year         = {{2022}},
}

@inproceedings{31805,
  author       = {{Kruse, Stephan and Bahmanian, Meysam and Fard, Saeed and Meinecke, Marc-Michael and Kurz, Heiko G. and Scheytt, Christoph}},
  booktitle    = {{European Radar Conference (EuRAD)}},
  title        = {{{A Low Phase Noise 77 GHz Frequency Synthesizer for Long Range Radar}}},
  doi          = {{10.23919/EuRAD54643.2022.9924677}},
  year         = {{2022}},
}

@inproceedings{29770,
  author       = {{Abughannam, Saed and Kruse, Stephan and Iftekhar, Mohammed and Scheytt, J. Christoph}},
  booktitle    = {{German Microwave Conference 2022 (GeMiC 2022)}},
  title        = {{{Design and Measurements of a Low-power Low-Date-rate Direct-detection Wireless Receiver with Improved Co-channel Interference Robustness}}},
  year         = {{2022}},
}

@article{34232,
  abstract     = {{<jats:p>In this paper, the theory of phase-locking of a microwave oscillator on the interharmonics, i.e. non-integer harmonics, of the repetition rate of the optical pulse train of a mode-locked laser (MLL) is developed. A balanced optical microwave phase detector (BOMPD) is implemented using a balanced Mach-Zehnder modulator and is employed to discriminate the phase difference between the envelope of the optical pulses and the microwave oscillator. It is shown mathematically that the inherent nonlinear properties of BOMPD with respect to the microwave excitation amplitude can be used for interharmonic locking. The characteristic functions of the phase detector for interharmonic locking are derived analytically and are compared with the measurement results. An opto-electronic phase-locked loop (OEPLL) is demonstrated whose output frequency locks on interharmonics of the MLL repetition rate when an appropriate modulator bias and sufficient RF amplitude are applied. Thus, for the first time theory and experiment of reliable locking on interharmonics of the repetition rate of a MLL are presented.</jats:p>}},
  author       = {{Bahmanian, Meysam and Kress, Christian and Scheytt, J. Christoph}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  number       = {{5}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Locking of microwave oscillators on the interharmonics of mode-locked laser signals}}},
  doi          = {{10.1364/oe.451894}},
  volume       = {{30}},
  year         = {{2022}},
}

@inproceedings{34233,
  author       = {{Singh, Karanveer and Kress, Christian and Mandalawi, Younus and Misra, Arijit and Preussler, Stefan and Scheytt, J. Christoph and Schneider, Thomas}},
  booktitle    = {{Next-Generation Optical Communication: Components, Sub-Systems, and Systems XI}},
  editor       = {{Li, Guifang and Nakajima, Kazuhide}},
  publisher    = {{SPIE}},
  title        = {{{Analysis of the effect of jitter and non-idealities on photonic digital-to-analog converters based on Nyquist pulses}}},
  doi          = {{10.1117/12.2609501}},
  year         = {{2022}},
}

@inproceedings{34234,
  author       = {{Singh, Karanveer and Meier, Janosch and Kress, Christian and Misra, Arijit and Schwabe, Tobias and Preussler, Stefan and Scheytt, J. Christoph and Schneider, Thomas}},
  booktitle    = {{Next-Generation Optical Communication: Components, Sub-Systems, and Systems XI}},
  editor       = {{Li, Guifang and Nakajima, Kazuhide}},
  publisher    = {{SPIE}},
  title        = {{{Emulation of integrated high-bandwidth photonic AWG using low-speed electronics}}},
  doi          = {{10.1117/12.2609416}},
  year         = {{2022}},
}

@article{34235,
  abstract     = {{<jats:p>We demonstrate for the first time, to the best of our knowledge, reconfigurable and real-time orthogonal time-domain detection of a high-bandwidth Nyquist signal with a low-bandwidth silicon photonics Mach-Zehnder modulator based receiver. As the Nyquist signal has a rectangular bandwidth, it can be multiplexed in the wavelength domain without any guardband as a part of a Nyquist-WDM superchannel. These superchannels can be additionally multiplexed in space and polarization. Thus, the presented demonstration can open a new possibility for the detection of multidimensional parallel data signals with silicon photonics. No external pulse source is needed for the receiver, and frequency-time coherence is used to sample the incoming Nyquist signal with orthogonal sinc-shaped Nyquist pulse sequences. All parameters are completely tunable in the electrical domain. The feasibility of the scheme is demonstrated through a proof-of-concept experiment over the entire C-band (1530 nm–1560 nm), employing a 24 Gbaud Nyquist QPSK signal due to experimental constraints on the transmitter side electronics. However, the silicon Mach-Zehnder modulator with a 3-dB bandwidth of only 16 GHz can process Nyquist signals of 90 GHz optical bandwidth, suggesting a possibility to detect symbol rates up to 90 GBd in an integrated Nyquist receiver.</jats:p>}},
  author       = {{Misra, Arijit and Kress, Christian and Singh, Karanveer and Meier, Janosch and Schwabe, Tobias and Preussler, Stefan and Scheytt, J. Christoph and Schneider, Thomas}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  number       = {{8}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Reconfigurable and real-time high-bandwidth Nyquist signal detection with low-bandwidth in silicon photonics}}},
  doi          = {{10.1364/oe.454163}},
  volume       = {{30}},
  year         = {{2022}},
}

@inproceedings{34236,
  abstract     = {{<jats:p>We report for the first time, inter-symbol-interference (ISI) free demultiplexing of Nyquist optical time division multiplexed (OTDM) signals using a reconfigurable orthogonal sinc-pulse sampling enabled by silicon photonic Mach-Zehnder Modulators.</jats:p>}},
  author       = {{Misra, Arijit and Singh, Karanveer and Meier, Janosch and Kress, Christian and Schwabe, Tobias and Preussler, Stefan and Scheytt, J. Christoph and Schneider, Thomas}},
  booktitle    = {{Conference on Lasers and Electro-Optics}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Flexible Time-Domain De-Multiplexing of Nyquist OTDM Channels by Orthogonal Sampling in Silicon Photonics}}},
  doi          = {{10.1364/cleo_si.2022.sth5m.2}},
  year         = {{2022}},
}