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DOE OSTI · 2507372

Quantum nonlocal modulation cancelation with distributed clocks

Abstract

We demonstrate nonlocal modulation of entangled photons with truly distributed radio frequency (RF) clocks. Leveraging a custom radio-over-fiber (RFoF) system characterized via classical spectral interference, we validate its effectiveness for quantum networking by multiplexing the RFoF clock with one photon from a frequency-bin-entangled pair and distributing the coexisting quantum-classical signals over fiber. Phase modulation of the two photons reveals nonlocal correlations in excellent agreement with theory: in-phase modulation produces additional sidebands in the joint spectral intensity, while out-of-phase modulation is nonlocally canceled. Our simple, feedback-free design attains subpicosecond synchronization—namely, drift less than ~0.5 ps in a 5.5 km fiber over 30 min (fractionally only ~2×10 -8 of the total fiber delay)—and should facilitate frequency-encoded quantum networking protocols such as high-dimensional quantum key distribution and entanglement swapping, unlocking frequency-bin qubits for practical quantum communications in deployed metropolitan-scale networks.

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Chapman, Stephen D. [Purdue University, West Lafayette, IN (United States)], Seshadri, Suparna [Purdue University, West Lafayette, IN (United States)] (ORCID:0000000228013538), Lukens, Joseph M. [Purdue University, West Lafayette, IN (United States); Arizona State University, Tempe, AZ (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000196504462), Peters, Nicholas A. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000272159630), McKinney, Jason D. [Purdue University, West Lafayette, IN (United States)], Weiner, Andrew M. [Purdue University, West Lafayette, IN (United States)], Lu, Hsuan-Hao [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000340090787). 2025-01-29. Quantum nonlocal modulation cancelation with distributed clocks. https://doi.org/10.1364/opticaq.539083

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