Abstract

Quantum Conference Key Agreement (QCKA) enables a group of users to generate a shared secret key, which reduces the latency and equipment overhead of establishing multiple Quantum Key Distribution (QKD) links. Conventional QCKA protocols send a multi-photon entangled state from one user to others and a key is generated only when all photons are detected, which is inefficient at high loss and opens side-channels at the receiver side. Here, we overcome this barrier through a multi-field QCKA protocol enabled by designing, fabricating, and testing an integrated photonic Green Machine that implements an eight-mode Hadamard unitary transformation through a beam-splitter network. With this integrated photonic circuit as a central untrusted relay, up to eight users can generate the same secure key upon measuring a single arriving photon. In addition to the first-ever realization and packaging of this integrated photonic Green Machine chip, we characterize the Green Machine and create a digital twin simulator which predicts that this chip enables multi-field QCKA among five users up to a range of 154 km between each party and a central relay.

Degree

College and Department

Ira A. Fulton College of Engineering; Electrical and Computer Engineering

Rights

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