Luca Planat is the CEO of Silent Waves, a startup company based in Grenoble developing, manufacturing and commercializing readout hardware for quantum computing.
Luca Planat owns an engineer degree (2016) from Grenoble INP Phelma and did a PhD in quantum physics between 2016 and 2020 at the Institut Néel, Grenoble, France. During his PhD, he focused on the development of wideband, near quantum limited, microwave amplifiers. These amplifiers are key pillars for large-scale quantum processor readout since they provide very high signal noise ratio over several gigahertz bandwidth. Early 2022, Luca Planat has co-founded Silent Waves, together with his former PhD supervisor, Nicolas Roch, and Baptiste Planat.
Superconducting parametric amplifiers have added noise about five times lower than current commercial microwave amplifiers based on high electron mobility transistors (HEMT). Used as pre-amplifiers with HEMT-based microwave amplifiers, superconducting parametric amplifiers allow to reach system noise substantially lower than with a HEMT amplifier alone. With this lower system noise, high-fidelity single shot qubit readout becomes possible, making superconducting parametric amplifiers crucial for qubit operations.
We will see that superconducting parametric amplifiers based on Josephson junctions are good candidates to work as pre-amplifiers in qubit readout lines. Their gain and added noise allow to reach high readout fidelities. However, as the number of qubit is expected to grow significantly, scalability becomes an important point to consider; other parameters than gain and added noise become critical, such as saturation and bandwidth, since the number of qubits per readout line becomes relevant. Also, parameters which are not directly related to the amplifier’s characteristics must be taken into consideration: scalability, reproducibility and robustness of the manufacture process become also highly relevant as the demand for these amplifiers is correlated with the growing number of qubits.
In this presentation, we will see how the traveling-wave architecture for parametric amplifiers can address these issues, and how Silent Waves traveling-wave parametric amplifiers are a solution for teams studying qubits working at cryogenic temperature. Finally, we will see what can be done to improve our current amplifiers, the solutions to be explored to improve the manufacture process, and what are the limitations in terms of performance and scalability of the current readout line architecture.