ABSTRACT

Integrated photonics has enabled much progress towards quantum technologies. However, many applications, e.g. quantum communication, sensing, and distributed and cloud quantum computing, require coherent photonic interconnection between separate sub-systems, with high-fidelity distribution and manipulation of entanglement between multiple devices being one of the most stringent requirements of the interconnected system. Coherently interconnecting separate chips is challenging due to the fragility of these quantum states and the demanding challenges of transmitting photons in at least two media within a single coherent system. Here, we report a quantum photonic interconnect demonstrating high-fidelity entanglement distribution and manipulation between two separate chips, implemented using state-of-the-art silicon photonics. Entangled states are generated and manipulated on-chip, and distributed between the chips by interconverting between path-encoding and polarisation-encoding. We use integrated state analysers to confirm a Bell-type violation of S=2.638+-0.039 between two chips. With improvements in loss, this quantum interconnect will provide new levels of flexible systems and architectures for quantum technologies.

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