Beijing Quantum Institute makes new progress in single-photon detection
Recently, Yuan Zhiliang's team (optical quantum communication and device team), the chief scientist of Beijing Institute of Quantum Information Science (Beijing Institute of Quantum Science), has used Ultra-narrowband interference circuits (UNIC) for the first time in the field of APD single-photon detection, effectively reducing the post-pulse noise and time jitter of single-photon detectors and achieving high counting rate. The research results are presented in the paper "Ultra-narrowband interference circuits enable low-noise and high-rate photon counting for InGaAs/InP avalanche photodiodes" (Ultra-narrowband interference circuits). The research results were published in Optics Express under the title "Ultra-narrowband interference circuits enable low-noise and high-rate photon counting for InGaAs/InP avalanche photodiodes" (Ultra-narrowband interference circuits enable low-noise and high-rate photon counting for InGaAs/InP APD single photon detectors).
Single-photon detector module with integrated very narrow-band interferometric circuit developed by the team
APD single-photon detectors use avalanche photodiodes and semiconductor cooling technology to provide size and cost advantages over superconducting nanowire single-photon detectors, which are widely used in engineering quantum communication networks.
In quantum communication applications, APD single-photon detectors generally operate in a gated manner, and the readout circuit needs to effectively suppress the gated capacitive response signal. The conventional readout circuit includes a self-differential circuit, an RF low-pass/band-pass filter circuit and an active counter-cancellation circuit. Self-differential circuit is large in size and the center frequency is sensitive to the phase drift of the device; RF low-pass/band-pass filter circuit will increase the time jitter of the readout signal due to the bandwidth limitation; active counter-cancellation circuit needs to adjust the inverse signal in real time to counteract the gated capacitive response signal, which is difficult to achieve stable operation in engineering.
To solve the above difficulties in gated single-photon detectors, the optical quantum communication and device team of Beijing Quantum Institute has innovatively applied the SAW technology, which is widely used in wireless communication, to single-photon detection, and achieved large bandwidth, high rejection ratio and low phase drift sensitivity through extremely narrow-band interferometric circuit, which effectively improves the performance of single-photon detectors. The maximum code rate of the QKD system with this detector is 25 Mb/s at 2 dB channel attenuation, which is a significant improvement compared with the maximum code rate of 13.72 Mb/s of the QKD system with a self-differential circuit detector.
The APD-M1 single-photon detection module will be applied to quantum communication and single-photon detection related scientific research and engineering projects, and further industrialized in the industry.
Yuanbin Fan, a senior engineer at Beijing Quantum Institute, and Tingting Shi (Institute of Semiconductors, Chinese Academy of Sciences), an intern, are the co-first authors of the paper, and Zhiliang Yuan, the chief scientist, is the corresponding author. The authors of the paper also include Weijie Ji, an engineer in the optical quantum communication and device team, Lai Zhou, an assistant researcher, and Yang Ji, a professor at the Institute of Semiconductors, Chinese Academy of Sciences.
