@inproceedings{58231, author = {{Kruse, Stephan and Surendranath Shroff, Vijayalakshmi and Bahmanian, Meysam and Brockmeier, Jan and Scheytt, J. Christoph}}, location = {{Dresden}}, title = {{{An Ultra Low Phase Noise Frequency Synthesizer with Optical Output for 77 GHz Photonic Radar}}}, year = {{2025}}, } @inproceedings{62682, author = {{Surendranath Shroff, Vijayalakshmi and Bahmanian, Meysam and Scheytt, J. Christoph}}, booktitle = {{2025 IEEE/MTT-S International Microwave Symposium - IMS 2025}}, publisher = {{IEEE}}, title = {{{Ultra-Low Phase Noise Frequency Synthesis Using Electro-Optic Detector-Based Comb-Microwave Synchronization}}}, doi = {{10.1109/ims40360.2025.11104035}}, year = {{2025}}, } @article{62683, author = {{Surendranath Shroff, Vijayalakshmi and Bahmanian, Meysam and Scheytt, J. Christoph}}, journal = {{IEEE Transactions on Microwave Theory and Techniques}}, publisher = {{IEEE}}, title = {{{Noise Folding in Optoelectronic PLLs for Ultralow Phase Noise: Modeling and Suppression With Experimental Validation}}}, doi = {{10.1109/TMTT.2025.3615413}}, year = {{2025}}, } @inproceedings{57103, author = {{Surendranath Shroff, Vijayalakshmi and Bahmanian, Meysam and Kruse, Stephan and Scheytt, J. Christoph}}, booktitle = {{2024 IEEE BiCMOS and Compound Semiconductor Integrated Circuits and Technology Symposium (BCICTS) }}, location = {{Fort Lauderdale, Florida}}, publisher = {{IEEE}}, title = {{{Design of an Ultra-Low Phase Noise Broadband Amplifier in 130 nm SiGe BiCMOS Technology}}}, doi = {{10.1109/BCICTS59662.2024.10745663}}, year = {{2024}}, } @misc{48623, abstract = {{Die Erfindung betrifft eine einstellbare Signalquelle mit kleinem Phasenrauschen, aufweisend • einen optischen Mikrowellenphasendetektor (BOMPD) aufweisend • einen Intensitätsmodulator (BIM), mit einem optischen Signaleingang, einem Modulationseingang (I), und einem ersten Ausgang (O1) und einen zweiten Ausgang (O2), • eine erste Photodiode (PD1), die im Betrieb mit Licht des ersten Ausgangs (O1) bestrahlt werden kann, • eine zweite Photodiode (PD2), die im Betrieb mit Licht des zweiten Ausgangs (O2) bestahlt werden kann, • wobei die erste Photodiode (PD1) und die zweite Photodiode (PD2), im Betrieb vorgespannt in Reihe geschaltet sind, • wobei zwischen der ersten Photodiode (PD1) und der zweiten Photodiode (PD2) ein Abgriff für eine Abgriffs-Signal angeordnet ist, • weiterhin aufweisend eine steuerbare Gleichstromquelle, • wobei am Abgriff im Betrieb mittels der ersten Gleichstromquelle (N4) ein Offsetstrom einstellbar ist, womit die Symmetrie des optischen Mikrowellenphasendetektor im Betrieb durch einen Offsetstrom aufgehoben wird, • wobei der Abgriff mit einem eventuellen Offsetstrom an ein Tiefpassfilter geführt wird, • wobei das tiefpassgefilterte Abgriffs-Signal einem einstellbaren Oszillator (OSZ) zur Verfügung gestellt wird. }}, author = {{Bahmanian, Meysam and Scheytt, J. Christoph}}, title = {{{Einstellbare Signalquelle mit kleinem Phasenrauschen}}}, year = {{2023}}, } @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{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}}, } @article{34232, abstract = {{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.}}, 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}}, } @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}}, } @article{29204, abstract = {{An analysis of an optical Nyquist pulse synthesizer using Mach-Zehnder modulators is presented. The analysis allows to predict the upper limit of the effective number of bits of this type of photonic digital-to-analog converter. The analytical solution has been verified by means of electro-optic simulations. With this analysis the limiting factor for certain scenarios: relative intensity noise, distortions by driving the Mach-Zehnder modulator, or the signal generator phase noise can quickly be identified.}}, author = {{Kress, Christian and Bahmanian, Meysam and Schwabe, Tobias and Scheytt, J. Christoph}}, journal = {{Opt. Express}}, keywords = {{Analog to digital converters, Diode lasers, Laser sources, Phase noise, Signal processing, Wavelength division multiplexers}}, number = {{15}}, pages = {{23671–23681}}, publisher = {{OSA}}, title = {{{Analysis of the effects of jitter, relative intensity noise, and nonlinearity on a photonic digital-to-analog converter based on optical Nyquist pulse synthesis}}}, doi = {{10.1364/OE.427424}}, volume = {{29}}, year = {{2021}}, } @inproceedings{23995, author = {{Kruse, Stephan and Bahmanian, Meysam and Kneuper, Pascal and Kress, Christian and Kurz, Heiko G. and Schneider, Thomas and Scheytt, Christoph}}, booktitle = {{The 17th European Radar Conference}}, title = {{{Phase Noise Investigation for a Radar System with Optical Clock Distribution }}}, doi = {{10.1109/EuRAD48048.2021.00018}}, year = {{2021}}, } @article{23993, author = {{Bahmanian, Meysam and Scheytt, Christoph}}, journal = {{IEEE Transactions on Microwave Theory and Techniques}}, number = {{3}}, pages = {{1635--1645}}, title = {{{A 2-20-GHz Ultralow Phase Noise Signal Source Using a Microwave Oscillator Locked to a Mode-Locked Laser}}}, doi = {{10.1109/tmtt.2020.3047647}}, volume = {{69}}, year = {{2021}}, } @inproceedings{24024, abstract = {{Recently it has been demonstrated that an optoelectronic phase-locked loop (OEPLL) using a mode-locked laser as a reference oscillator achieves significantly lower phase noise than conventional electronic frequency synthesizers. In this paper a concept for an OEPLL-based frequency synthesizer is presented and it is investigated how it can be used as a local oscillator (LO) for THz transceivers in order to improve the signal quality in THz wireless communications. The concept of the OEPLL is presented and it's measured phase noise is compared to the phase noise of a laboratory-grade electronic frequency synthesizer. The measured phase noise spectra of both synthesizers at 10 GHz are then used to model LO phase noise at 320 GHz. Based on models of generic zero-IF transmit and receive frontends, THz signals with different modulation formats and Baud rates are simulated at system level using the modeled LO phase noise for the two LO approaches. Finally, the results are compared.}}, author = {{Scheytt, Christoph and Wrana, Dominik and Bahmanian, Meysam and Kallfass, Ingmar}}, booktitle = {{2020 Third International Workshop on Mobile Terahertz Systems (IWMTS)}}, location = {{Essen, Germany }}, title = {{{Ultra-Low Phase Noise Frequency Synthesis for THz Communications Using Optoelectronic PLLs}}}, doi = {{10.1109/IWMTS49292.2020.9166347}}, year = {{2020}}, } @inproceedings{24023, abstract = {{This paper presents an ultra-wideband and ultra-low noise frequency synthesizer using a mode-locked laser as its reference. The frequency synthesizer can lock in the frequency range from 2 GHz to 20 GHz on any harmonic of a mode-locked laser optical pulse train. The integrated rms-jitter (1 kHz-100 MHz) of the synthesizer is less than 5 fs in the frequency range from 4 GHz to 20 GHz with a typical value of 4 fs and a minimum of 3 fs. This is the first reported wideband phase locked loop achieving sub-10 fs rms-jitter for offset frequencies larger than 1 kHz.}}, author = {{Bahmanian, Meysam and Fard, Saeed and Koppelmann, Bastian and Scheytt, Christoph}}, booktitle = {{ 2020 IEEE/MTT-S International Microwave Symposium (IMS)}}, publisher = {{IEEE}}, title = {{{Wide-Band Frequency Synthesizer with Ultra-Low Phase Noise Using an Optical Clock Source}}}, doi = {{10.1109/IMS30576.2020.9224118}}, year = {{2020}}, } @inproceedings{24055, abstract = {{An octave-band voltage-controlled oscillator is phase-locked on the envelope of the pulse train from a mode-locked laser. The locking scheme employs a balanced Mach-Zehnder modulator with two photodiodes as a phase detector. The phase.locked loop has a loop bandwidth of approximately 1MHz and an in-band phase noise of approximately -135dBc/Hz at all frequencies. The integrated jitter from 1kHz to 100MHz is 21fs, 18.3fs and 13.8fs at 5.016GHz, 7.6GHz and 10.032GHz carrier frequencies, respectively. To the authors' knowledge, this is the best jitter performance reported for a PLL with MZM-based phase detection and the first reported PLL of this type featuring an octave-band frequency range.}}, author = {{Bahmanian, Meysam and Tiedau, Johannes and Silberhorn, Christine and Scheytt, Christoph}}, booktitle = {{2019 International Topical Meeting on Microwave Photonics (MWP)}}, pages = {{1--4}}, title = {{{Octave-Band Microwave Frequency Synthesizer Using Mode-Locked Laser as a Reference}}}, doi = {{10.1109/MWP.2019.8892046}}, year = {{2019}}, } @misc{24792, author = {{Bahmanian, Meysam and Scheytt, Christoph}}, title = {{{Theory of an Optoelectronic Microwave Phase-locked Loop based on a MLL reference and MZM-based Optoelectronic Phase Detection}}}, year = {{2019}}, }