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arXiv · 2602.24098

A frequency-agile microwave-optical interface for superconducting qubits

Yufeng Wu·Yiyu Zhou·Haoqi Zhao·Danqing Wang·Matthew D. LaHaye·Daniel L. Campbell·Hong X. Tang
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Abstract

Superconducting quantum processors operate at microwave frequencies in millikelvin environments, making it challenging to interconnect distant nodes using conventional microwave wiring. Coherent microwave-to-optical (M2O) transduction enables superconducting quantum networks by interfacing itinerant microwave photons with low-loss optical fiber. However, many state-of-the-art transducers provide efficient conversion only over a narrow frequency span, complicating deployment with heterogeneous superconducting devices that are detuned by gigahertz-scale offsets. Here we demonstrate a frequency-agile microwave-optical interface that overcomes this bandwidth mismatch by cascading an electro-optic M2O transducer with a multimode microwave-to-microwave (M2M) frequency converter, with in situ tunability of the microwave resonances in both stages. Using this architecture, we realize continuous frequency coverage from 5.0 to 8.5 GHz within a single system. As an application relevant to superconducting-qubit networking, we use the cascaded M2M-M2O interface to optically read out a superconducting qubit whose readout resonator is detuned by 1.7 GHz from the native M2O microwave resonance, demonstrating a scalable route toward fiber-linked superconducting quantum nodes.

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Yufeng Wu, Yiyu Zhou, Haoqi Zhao, Danqing Wang, Matthew D. LaHaye, Daniel L. Campbell, Hong X. Tang. 2026-02-27. A frequency-agile microwave-optical interface for superconducting qubits. https://arxiv.org/abs/2602.24098

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