Abstract: Quantum frequency conversion (QFC) and optical nonreciprocity are key capabilities for scalable and noise-resilient quantum networks. We demonstrate efficient, low-noise, and bidirectional QFC between the telecom (1550 nm) and visible (780 nm) bands using unpoled InGaP (χ²) nanophotonic waveguides, achieving record-low pump power and high loss-inclusive conversion efficiency without relying on long-wavelength pumps. Leveraging the same InGaP platform, we further realize magnetic-free optical nonreciprocity—including isolation and circulation—at the single-photon level through noiseless all-optical frequency conversion on a photonic chip. Both demonstrations preserve quantum coherence and entanglement of the input photons, marking significant advances in integrated nonlinear photonics and toward programmable, directional, and scalable quantum networks.
Bio: Jierui Hu is a 2nd year ECE graduate student in Kejie Fang’s group researching integrated quantum photonics.