Photonic interface links atom qubits

A research group from Japan has set a world record by demonstrating a 10-channel multiplexed quantum photonic interface. The work, published in the journal Optica on September 1, 2026, is a critical step toward linking multiple quantum computers with light.

Neutral-atom quantum computers typically use arrays of about 10,000 atoms as qubits. Building a fault-tolerant universal quantum computer, however, is expected to require over one million qubits for error correction. A promising path to that scale involves networking many smaller quantum processors together by distributing entangled photons between them. This demands a photonic interface capable of linking many qubits in parallel, a capability previous fiber-based approaches lacked.

From fiber limits to waveguide arrays

The team, led by Professor Takashi Yamamoto of the University of Osaka's Center for Quantum Information and Quantum Biology, developed a new optical system. They collaborated with the National Institute of Information and Communications Technology (NICT) and Hamamatsu Photonics K.K. Their system uses an integrated optical waveguide array to achieve parallel photon delivery and detection from a neutral-atom array.

In the experiment, photons emitted from ten atoms spaced at micrometer intervals were coupled into ten parallel channels of a 32-channel waveguide array. The photons were then transmitted through optical fibers and detected in parallel. The researchers confirmed negligible crosstalk between channels. They also verified correlations between the quantum states of the atoms and the polarization states of the emitted photons. This supports the interface's potential for creating multiplexed atom-photon entanglement, a necessity for quantum-processor networking. The approach is believed to be scalable to roughly 100 parallel channels.

A custom-built detection system

Photon detection for this experiment required a specialized system. The team used a multichannel superconducting nanostrip photon detector system based on technology from Shigehito Miki at NICT. This system was newly developed as a research platform for this project by Hideki Shimoi of Hamamatsu Photonics K.K.

Professor Yamamoto highlighted the collaborative achievement. "Through research and development spanning from neutral-atom arrays to superconducting nanostrip photon detector systems, we have achieved the first demonstration of a multiplexed optical interface," he said. The team now aims to scale up the multiplexing further and work toward the practical interconnection of neutral-atom quantum computers.

Enabling networked quantum architectures

This research marks significant progress toward networked quantum computers with the scalability required for fault-tolerant universal quantum computing. By allowing multiple quantum processors to be interconnected through parallel photonic links, the technology could enable large-scale quantum computing architectures. These would function similarly to modern data centers, where numerous computing modules collaborate as a single, powerful system.