Researchers in China have developed a 100-channel single-photon detector, marking a significant advancement that could accelerate the deployment of large-scale broadband quantum networks. The innovation, achieved by a team at the Shanghai Institute of Microsystems and Information Technology (SIMT) under the Chinese Academy of Sciences, addresses a key technical bottleneck in photonic quantum technologies related to scaling detection capabilities.

Single-photon detectors are critical components for various quantum applications, including quantum computing, communications, and precision metrology. These detectors rely on superconducting nanowire technology, which can detect individual photons with efficiencies approaching 100 percent. However, existing systems have been limited to supporting a maximum of about 32 detection channels due to challenges in managing heat transfer and maintaining cryogenic temperatures necessary for detector operation.

Superconducting nanowire detectors require cooling to near absolute zero temperatures, typically below 2.1 Kelvin (-271 degrees Celsius). Traditionally, coaxial cables—used to connect the detectors within the cryogenic environment to room-temperature electronics—conduct significant heat back into the cryostat. This thermal load increases with the number of channels, limiting the system’s scalability due to the cooling power required and increased physical bulk of cable assemblies.

To overcome this constraint, the Shanghai-based research team developed a novel interconnect system using ultra-thin, flexible high-density multi-core microstrip lines. This new cabling solution exhibits low thermal conductivity, reducing heat leakage into the cryostat to less than 5 percent of that seen with conventional thick metal cables. The design allows for over 100 independent detection channels to operate simultaneously while maintaining the ultra-low temperatures required for superconducting operation.

In tests conducted over seven days with continuous 24-hour operation, the cryogenic platform remained stable at temperatures below 2.1 K. All detection channels demonstrated system efficiencies exceeding 80 percent, confirming the reliability and effectiveness of the new approach. The researchers also incorporated architectural innovations to ensure stability and miniaturization of the large-scale detector array.

The team’s results were published in the journal Laser & Photonics Reviews in late September. Their work is seen as a foundational step toward scalable, parallel photonic quantum detection systems, facilitating broader adoption of quantum photonic technologies beyond laboratory settings into practical, large-scale applications such as quantum broadband communication networks and advanced sensing technologies.