A heterogeneously integrated coupled-cavity frequency beam splitter

Frequency encoded photonic qubits promise a scalable path towards high-dimensional quantum information processing, but require efficient components for coherently mixing frequency modes. Coupled cavity modulators provide this functionality by using only a single driving microwave tone to couple hybridized optical supermodes. Here, we demonstrate a heterogeneously integrated thin-film lithium-niobate-on-silicon coupled-cavity modulator that realizes tunable bidirectional frequency mode transformations, including (50/50) beam splitting and near complete frequency swapping with (>20~\mathrm{dB}) pump extinction at a (10~\mathrm{GHz}) supermode splitting. Because the electro-optic film is bonded onto a foundry fabricated silicon photonics platform, the approach is compatible with co-integration of photon pair sources, spectral filters, active tuning elements, and single photon detectors. We also bond thin-film lithium tantalate onto the same coupled-cavity platform, demonstrating material flexibility for scalable integrated frequency bin quantum photonic circuits.

Source: arXiv:2608.26028v1 - http://arxiv.org/abs/2608.26028v1 PDF: https://arxiv.org/pdf/2608.26028v1 Original Link: http://arxiv.org/abs/2608.26028v1