Chinese team builds a 100-channel single-photon detector for quantum networks

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Chinese scientists have built a single photon detector system with 100 channels, far more than the usual limit. Interesting Engineering's Ameya Paleja reports on the work by the Shanghai Institute of Microsystem and Information Technology, published in Laser and Photonics Reviews

The detectors use superconducting nanowires, which are extremely sensitive to single particles of light. Most systems are limited to about 32 channels, partly because each one needs cabling that carries heat into the cryostat. The team replaced bulky coaxial cables with flexible, high density microstrip lines

That change cut the heat load to about one twenty first of conventional cabling. The cooling chamber stayed below 2.1 kelvin during a seven day test, and the channels reached 80 percent detection efficiency with very few false counts

The team also built a prototype entanglement distribution network with five users and ten two way links. The fidelity of the shared entanglement was above 90 percent, which shows the system works in a realistic setting

Single photon detectors are a key part of quantum communication and photonic quantum computing. Scaling the number of channels is essential for larger networks. The wiring solution here echoes the cabling problems we keep discussing for qubits

Is wiring the hidden challenge in all of quantum technology? And how close are quantum networks to practical use?

100-channel single-photon detector opens doors to quantum internetinterestingengineering.com