Silent Waves publishes TWPAI findings in Nature Electronics
November 7, 2025 — Grenoble, France
A significant scientific milestone has been achieved with the publication of “A traveling wave parametric amplifier isolator” in Nature Electronics. The research results from a collaboration between Institut Néel (University Grenoble Alpes CNRS Grenoble INP), Silent Waves, Karlsruhe Institute of Technology, and the University of Strasbourg, led by Arpit Ranadive and supervised by Dr Nicolas Roch, co-founder of Silent Waves.
The work demonstrates a new device that brings high gain and strong isolation together within a single traveling wave parametric amplifier. Built from a Josephson junction based SNAIL metamaterial, the TWPAI provides up to 20 dB of forward gain, 30 dB of reverse isolation, and maintains near quantum limited added noise across a static 3 dB bandwidth greater than 500 MHz.
A more compact and efficient architecture
Quantum readout chains must detect ultra low power microwave signals with minimal noise and without allowing radiation to travel back to the device under test. Current systems rely on multiple cryogenic insulators that consume space inside dilution refrigerators and introduce dissipation that reduces overall performance.
By integrating isolation directly into the amplifier, the TWPAI offers a route toward readout lines that do not rely on bulky cryogenic insulators. This enables more compact and efficient architectures for next generation quantum processors and precision measurement systems.
Amplification & Isolation in one device
The device uses a SNAIL-based metamaterial that provides both:
- Four wave mixing for forward amplification
- Three wave mixing upconversion to suppress backward traveling modes
A dynamic phase matching mechanism balances dispersion, Kerr effects and higher order mixing processes. This ensures stable parametric interactions along the 6 mm transmission line and broadband produces gain and isolation with near quantum limited noise.
“By integrating isolation directly into the amplifier we remove one of the main obstacles to compact high fidelity quantum readout chains and move closer to practical large-scale quantum processors.” ”
Dr. Nicolas Roch, CSO
Silent Waves' Role in this TWPA breakthrough
Although this research was conducted at Institut Néel, it shares the same scientific foundations that guided the creation of Silent Waves. As a co-founder, Nicolas Roch continues to contribute to both academic research and the development of next generation readout solutions.
Silent Waves focuses on providing ultra-low noise microwave amplification and support for research teams working in quantum computing, radio astronomy and electron spin resonance. Scientific advances such as the TWPAI reinforce the long term roadmap of integrated and scalable readout electronics.
About Silent Waves
Silent Waves designs, manufactures and commercializes ultra-low-noise superconducting amplifiers based on Josephson junctions and traveling-wave architectures. Its traveling-wave parametric amplifiers (TWPAs) are primarily used for fast and high-fidelity cryogenic qubit readout in superconducting quantum computers.
Compact, reliable, and high performance, these amplifiers are a critical building block for scaling quantum computers to hundreds of thousands of qubits.
Founded in 2022 in Grenoble, France, Silent Waves now serves customers on three continents.
Website: www.silent-waves.com
Press contact
Andrea Busch, Head of Marketing & Communications
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