[Press Release]A Multiplexed Quantum Photonic Interface for Neutral-Atom Quantum Computers: — New Technology for Large-Scale Networked Quantum Computers — 

A research group in Japan led by Professor YAMAMOTO Takashi, Deputy Director, Center for Quantum Information and Quantum Biology / Graduate School of Engineering Science, the University of Osaka, in collaboration with the National Institute of Information and Communications Technology (NICT) and Hamamatsu Photonics K.K., has successfully demonstrated a world-record 10-channel multiplexed quantum photonic interface based on an integrated waveguide array, a key technology for optically interconnecting multiple quantum computers.

Neutral-atom quantum computers are expected to use arrays of approximately 10,000 atoms, with each atom serving as a qubit. However, fault-tolerant universal quantum computers are expected to require more than one million qubits for error correction. One promising route to this scale is therefore to interconnect multiple quantum processors by distributing entangled photons between them. This requires a multiplexed quantum photonic interface capable of linking many qubits in parallel.

Previous multiplexing approaches mainly relied on parallel optical fibers and were limited to only a few channels. Their insufficient integration density and wide atom spacing also made them difficult to apply to conventional neutral-atom quantum computers.

In this study, Professor YAMAMOTO’s research group developed an optical system incorporating an integrated optical waveguide array and demonstrated parallel photon delivery and detection from a neutral-atom array. Photons emitted from 10 atoms spaced at micrometer-scale intervals were coupled into 10 parallel channels of a 32-channel waveguide array, transmitted through optical fibers, and detected in parallel.

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