Hong-Ou-Mandel Interference with a Coexisting Clock using Transceivers for Synchronization over Deployed Fiber

Abstract

Interference between independently generated photons is a key step towards distributing entanglement over long distances, but it requires synchronization between the distantly-located photon sources. Synchronizing the clocks of such photon sources using coexisting two-way classical optical communications over the same fiber that transport the quantum photonic signals is a promising approach for achieving photon-photon interference over long distances, enabling entanglement distribution for quantum networking using the deployed fiber infrastructure. Here, we demonstrate photon-photon interference by observing the Hong-Ou-Mandel dip between two distantly-located sources: a weak coherent state source obtained by attenuating the output of a laser and a heralded single-photon source. We achieve a maximum dip visibility of $0.58\pm 0.04$ when the two sources are connected via $4.3$ km of deployed fiber. Dip visibilities $>0.5$ are nonclassical and a first step towards achieving teleportation over the deployed fiber infrastructure. In our experiment, the classical optical communication is achieved with $-21$ dBm of optical signal launch power, which is used to synchronize the clocks in the two independent, distantly-located photon sources. The impact of spontaneous Raman scattering from the classical optical signals is mitigated by appropriate choice of the quantum and classical channel wavelengths. All equipment used in our experiment (the photon sources and the synchronization setup) is commercially available. Finally, our experiment represents a scalable approach to enabling practical quantum networking with commercial equipment and coexistence with classical communications in optical fiber.

References in corpus (18)

• Photonic quantum information processing: a concise review
• Longer-Baseline Telescopes Using Quantum Repeaters
• Quantum teleportation across a metropolitan fibre network
• Towards a Distributed Quantum Computing Ecosystem
• Proof-of-principle demonstration of measurement-device-independent quantum key distribution using polarization qubits
• Two-photon interference: the Hong-Ou-Mandel effect
• Implementation of a 46-node quantum metropolitan area network
• Heralded single-photon source utilizing highly nondegenerate, spectrally factorable spontaneous parametric downconversion
• Deploying an inter-European quantum network
• Hong-Ou-Mandel Interference with Imperfect Single Photon Sources
• Hertz-rate metropolitan quantum teleportation
• Design and Implementation of the Illinois Express Quantum Metropolitan Area Network
• Long-distance practical quantum key distribution by entanglement swapping
• Deployed MDI-QKD and Bell-State Measurements Coexisting with Standard Internet Data and Networking Equipment
• Development of a Boston-area 50-km fiber quantum network testbed
• Designing Noise-Robust Quantum Networks Coexisting in the Classical Fiber Infrastructure
• Metropolitan-scale Entanglement Distribution with Co-existing Quantum and Classical Signals in a single fiber
• Picosecond Synchronization of Photon Pairs through a Fiber Link between Fermilab and Argonne National Laboratories

Cited by in corpus (2)

• Quantum entanglement distribution coexisting with high-rate, broadband classical optical communications over a real-world fiber connecting remote, synchronized nodes
• Crosstalk Analysis in Quantum Networks: Detection and Localization Insights with photon counting OTDR