everything RF recently interviewed Dr. Peter Hertenstein, the Chief Executive Officer and Co-Founder of QuSine, a German deep-tech company pioneering opto-electronic RF and microwave signal sources with ultra-low phase noise and jitter. He holds a Ph.D. from the University of Cambridge and brings a strong background in business and management. Before founding QuSine, Dr. Hertenstein held leadership roles in strategy consulting and business development. A strong advocate for integrating photonics and electronics to overcome traditional RF limitations, Dr. Hertenstein is passionate about enabling a new generation of precision systems that will define the future of signal performance.
Q. Could you share a brief overview of QuSine? When was the company founded, what inspired its creation, and which core challenges in RF and frequency are you aiming to solve?
Dr. Peter Hertenstein: QuSine is developing the next generation of RF and microwave signal generators with ultra-high precision for demanding applications in test and measurement equipment, metrology, and emerging fields such as quantum technologies, advanced communications, and radar systems. Rooted in opto-electronic technologies, we push phase-noise and jitter performance far beyond what conventional electronic approaches can deliver, enabling our customers to build higher-performance systems.
The company was founded in 2024 as a spin-off from the University of Paderborn. The original idea for our architecture was developed by Prof. Christoph Scheytt. QuSine grew out of academic and laboratory research on opto-electronic and photonic oscillators and the realization that many emerging applications — from quantum systems and 6G to high-resolution radar and space timing — are fundamentally limited by the quality of their reference signals, particularly phase noise and jitter. Solving that bottleneck became our mission.
Q. What led you to focus on opto-electronic technology for developing oscillators and signal generators? What are the main advantages of this approach over traditional technologies?
Dr. Peter Hertenstein: Opto-electronic signal sources exploit the extremely low noise and wide bandwidth properties of optical frequency combs and transfer that stability to the microwave and RF domains. Compared with purely electronic oscillators, the advantages are significant: orders-of-magnitude improvements in phase noise, single-digit-femtosecond jitter, exceptionally clean spectral purity (low spurs), and the ability to generate stable signals at tens of gigahertz without the phase-noise penalties typical of electronic multipliers. These benefits are why we chose opto-electronic architectures as the foundation for our oscillators and forthcoming signal generators.
Q. Can you tell us about the opto-electronic RF/microwave frequency oscillator series you’ve developed and the target markets for these products?
Dr. Peter Hertenstein: Our first commercial family is the PureWave Photonic Microwave Oscillator (PMO) — a fixed-frequency, ultra-low-noise oscillator series in a compact format, available across a wide frequency range (from a few GHz up to tens of GHz, in 1-GHz steps).
They are designed for customers who need the cleanest possible reference signals: quantum technology laboratories, high-end communications testbeds, advanced radar systems, precision timing and space applications, and other R&D or production environments where phase noise is the limiting factor.
The PureWave PMO offers measured phase noise of approximately −154 dBc/Hz at 10 GHz and a 100 kHz offset, along with single-digit femtosecond jitter — positioning the family as performance-oriented solutions for both laboratory and system integration.
Opto-electronic RF/Microwave Frequency Oscillator from QuSine
Q. You’re also developing an opto-electronic-based RF/microwave signal generator. How does it differ from conventional signal generators, and when can we expect its launch?
Dr. Peter Hertenstein: Our upcoming signal generator builds on the same opto-electronic core philosophy but adds frequency agility, user control, and a modern bench-top form factor. It offers adjustable frequencies across a wide band — initially 8–12 GHz, with options extending down to 3 GHz or up to 20 GHz — while maintaining extremely low phase noise, jitter, and spurious levels.
Because its noise floor is defined by the optical reference and photonic loop, rather than by electronic oscillators or multipliers, it preserves superior phase-noise performance across its entire output range. This is a fundamental advantage over conventional signal generators, which are limited by the phase noise of their OCXO or Rubidium reference clocks.
While many commercial signal generators include functions such as modulation schemes, amplitude sweeps, or fast frequency switching, our initial focus is on providing ultra-pure sine-wave reference sources — the foundation for high-performance test and measurement systems.
We have been demonstrating prototypes and are currently conducting a staged rollout, delivering early units to selected customers before the full commercial launch. (Exact availability timelines are being communicated directly to customers; please contact our sales team for details.)
Upcoming Opto-electronic RF/Microwave Signal Generator from QuSine
Q. Phase noise and jitter performance in your technology seem exceptional. Could you explain what phase noise and jitter are, and why they matter in real-world applications?
Dr. Peter Hertenstein: Simply put, phase noise describes short-term random fluctuations in an oscillator’s phase (typically plotted as dBc/Hz versus offset frequency), while jitter represents the time-domain manifestation — the variation in timing of signal cycles, often measured in femtoseconds over a specific offset band.
These parameters are critical because nearly every RF and analog system relies on an oscillator as a timing or frequency reference. High phase noise or jitter directly degrades receiver sensitivity, increases bit-error rates in advanced modulation schemes, limits radar resolution and detection range, and reduces fidelity in quantum control pulses. Improving these parameters leads to cleaner measurements, longer detection ranges, lower error rates, and more reliable quantum operations.
Q. How does QuSine approach phase noise optimization in high-frequency or wideband systems? Are there unique architectures or techniques you’ve developed?
Dr. Peter Hertenstein: We have developed and patented a unique architecture that allows us to flexibly generate RF signals from photonic sources. The innovation lies both in the system architecture and at the component level. Building on this patented foundation, we’ve also developed proprietary techniques for designing phase-locked loops (PLLs) with exceptional performance, enabling us to achieve extremely low phase noise even at high frequencies.
Q. What are the key differentiators that set QuSine apart from other companies in the high-performance oscillator and signal generator space?
Dr. Peter Hertenstein: There are three primary differentiators:
- Exceptional performance through optical-first architecture — our signal floor is determined in the optical domain, not by RF components.
- Compact form factor — compared with other photonic RF signal sources offering similar phase-noise performance, our systems are far more compact, comparable in size to conventional RF signal generators.
- Scalability and cost efficiency — we strive for industrial-grade products rather than setting world records in low noise. This approach enables scalability and makes ultra-low phase-noise technology accessible across markets such as quantum, radar, advanced communications, and space.
We are also working toward integrated, turn-key modules that allow system designers to easily incorporate photonic performance into their RF systems.
Q. Can you share a real-world example where QuSine’s technology significantly improved system performance or solved a complex RF challenge that traditional solutions could not?
Dr. Peter Hertenstein: While I cannot name specific customers or projects, one representative example comes from radar prototyping, where our oscillators have been used as ultra-low-noise local oscillators (LOs). The result was a measurable improvement in system metrics — particularly enhanced small-target detectability.
These are precisely the scenarios where the performance limits of the LO previously masked the overall system capability. Once the reference noise floor was lowered, the downstream system performance improved significantly.
Q. How does the cost of opto-electronic oscillators and generators compare to traditional solutions?
Dr. Peter Hertenstein: Photonics-based systems have traditionally been associated with high cost, large form factors, and sensitivity to environmental factors such as vibration or temperature fluctuations. By focusing on scalable, industrial-grade designs, we have been able to significantly reduce cost and complexity, bringing our products to the price range of leading low-phase-noise generators from major T&M vendors.
We provide quotations upon request, as most customers approach us with unique specifications that require a degree of customization.
Q. When did you launch your first product, and what has been the market feedback so far?
Dr. Peter Hertenstein: We announced our first product family, the PureWave Photonic Microwave Oscillators, in late 2024 and updated the line in 2025 with integrated laser sources. Feedback from early customers, trade-show attendees, and industry media has been very encouraging.
Technical publications such as Microwave Journal have featured our products, and coverage of our upcoming signal generator has generated strong interest. Customers consistently highlight our phase-noise and jitter performance as the primary reason for evaluating or integrating our units.
Q. What’s next for QuSine? Are there any upcoming product lines, partnerships, or technological breakthroughs on the horizon?
Dr. Peter Hertenstein: We recently announced a partnership with the Fraunhofer Heinrich Hertz Institute in Berlin, where we are collaborating on component-level improvements and exploring new application domains for our technology, and are working on forging further partnerships that we can announce soon. We are also looking for additional industrial partnerships and collaborations to bring the technology into defence, communication and quantum applications.
We also maintain close collaboration with our “mother” institution, the University of Paderborn, where we continue to advance the underlying technology. We are making significant progress and expect to announce further breakthroughs in the near future.
In terms of our product roadmap, our current focus is on finalizing and launching the opto-electronic signal generator, as well as efforts to miniaturize our technology – two key steps in bringing photonic-grade precision to the broader RF market. Our long-term goal is to make opto-electronic precision as accessible and deployable as conventional RF technologies.
About QuSine
QuSine is a young spin-off from the University of Paderborn dedicated to developing high-precision signal synthesizers with best-in-class phase noise and jitter performance. The company is pioneering the next generation of signal generators through advanced opto-electronic technology, achieving levels of precision that were previously unattainable. This breakthrough enables significant progress across a range of applications that demand exceptional signal stability and accuracy.
Supported by the Federal Agency for Breakthrough Innovation (SPRIN-D) and the German Federal Ministry for Economic Affairs and Climate Protection (BMWK) through the EXIST Research Transfer programme, QuSine is translating cutting-edge research into transformative, real-world solutions for ultra-precise signal generation.
