Linking superconducting quantum devices to optical fibers via microwave-optical quantum transducers may enable large-scale quantum networks. For this application, transducers based on the Pockels electro-optic (EO) effect are promising for their direct conversion mechanism, high bandwidth, and potential for low-noise operation. However, previously demonstrated EO transducers require large optical pump power to overcome weak EO coupling and reach high efficiency. Here, we create an EO transducer in thin-film lithium niobate, a platform that provides low optical loss and strong EO coupling. We demonstrate on-chip transduction efficiencies of up to $(2.7 \pm 0.3) \times {10^{- 5}}$ and $(1.9 \pm 0.4) \times {10^{- 6}}/{\unicode{x00B5}{\rm W}}$ of optical pump power. The transduction efficiency can be improved by further reducing the microwave resonator’s piezoelectric coupling to acoustic modes, increasing the optical resonator quality factor to previously demonstrated levels, and changing the electrode geometry for enhanced EO coupling. We expect that with further development, EO transducers in thin-film lithium niobate can achieve near-unity efficiency with low optical pump power.

中文翻译：

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薄膜铌酸锂中的腔电光学，可实现有效的微波到光学的转导

通过微波光量子换能器将超导量子设备链接到光纤可以实现大规模量子网络。对于此应用，基于Pockels电光（EO）效应的换能器因其直接转换机制，高带宽和低噪声运行潜力而备受期待。但是，先前演示的EO换能器需要较大的光泵浦功率才能克服弱EO耦合并达到高效率。在这里，我们用薄膜铌酸锂创建了一个EO换能器，该平台可提供低光损耗和强EO耦合。我们展示了高达$（2.7 \ pm 0.3）\ times {10 ^ {-5}} $和$（1.9 \ pm 0.4）\ times {10 ^ {-6}} / {\ unicode的片上转导效率{x00B5} {\ rm W}} $光泵功率。通过进一步减少微波谐振器与声模的压电耦合，将光学谐振器品质因数提高到先前证明的水平以及更改电极几何形状以增强EO耦合，可以提高转换效率。我们期望随着进一步的发展，薄膜铌酸锂中的EO换能器能够以低的光泵浦功率实现接近统一的效率。