Coherent microwave comb generation via the Josephson effect

Angelo Greco; Xavier Ballu; Francesco Giazotto; Alessandro Crippa

doi:10.1038/s41467-026-69652-1

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arXiv · 2503.13259

Coherent microwave comb generation via the Josephson effect

Angelo Greco·Xavier Ballu·Francesco Giazotto·Alessandro Crippa

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Abstract

Frequency combs represent exceptionally precise measurement tools due to the coherence of their spectral lines. While optical frequency comb sources constitute a well-established technology, superconducting circuits provide a relatively unexplored on-chip platform for low-dissipation comb emitters able to span from gigahertz to terahertz frequencies. We demonstrate coherent microwave frequency comb generation by leveraging the ac Josephson effect in a superconducting quantum interference device. A time-dependent magnetic drive periodically generates voltage pulses, which in the frequency domain correspond to a comb with dozens of spectral modes. The micrometer-scale footprint and minimal dissipation inherent to superconducting systems foster the integration of our comb generator with advanced cryogenic electronics. Transferring optical techniques to the solid-state domain may enable new applications in quantum technologies.

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Angelo Greco, Xavier Ballu, Francesco Giazotto, Alessandro Crippa. 2025-03-17. Coherent microwave comb generation via the Josephson effect. https://doi.org/10.1038/s41467-026-69652-1

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