Path-encoded multidimensional entanglement distribution between integrated photonic devices through multi-core fibre

Here we present the experimental distribution of four-dimensional entangled qudits between integrated photonic devices. Qudits offer advantages over qubits such as higher information capacity, and improved noise robustness. Integrated photonics allows for the reliable preparation and manipulation of large-scale entangled quantum states on a single device, with outstanding phase stability. However, reliable transmission of these states between devices, integrated or otherwise, has been a challenge, mainly due to the difficulty of maintaining phase stability between multiple optical channels. We implement an active phase stabilisation algorithm, utilising the same circuitry as for the quantum states, enabling stable distribution of qudits.