Experimental Twin-Field Quantum Key Distribution over 1000 km Fiber Distance.

Quantum key distribution (QKD) aims to generate secure private keys shared by two remote parties. With its security being protected by principles of quantum mechanics, some technology challenges remain towards practical application of QKD. The major one is the distance limit, which is caused by the fact that a quantum signal cannot be amplified while the channel loss is exponential with the distance for photon transmission in optical fiber. Here using the 3-intensity sending-or-not-sending protocol with the actively-odd-parity-pairing method, we demonstrate a fiber-based twin-field QKD over 1002 km. In our experiment, we developed a dual-band phase estimation and ultra-low noise superconducting nanowire single-photon detectors to suppress the system noise to around 0.02 Hz. The secure key rate is 9.53×10^{-12} per pulse through 1002 km fiber in the asymptotic regime, and 8.75×10^{-12} per pulse at 952 km considering the finite size effect. Our work constitutes a critical step towards the future large-scale quantum network.

[1]  Xiang‐Bin Wang,et al.  Universal approach to sending-or-not-sending twin field quantum key distribution , 2022, Quantum Science and Technology.

[2]  Zong-Wen Yu,et al.  Composable security for practical quantum key distribution with two way classical communication , 2021, New Journal of Physics.

[3]  Jian-Wei Pan,et al.  Twin-field quantum key distribution over a 511 km optical fibre linking two distant metropolitan areas , 2021, Nature Photonics.

[4]  Jian-Wei Pan,et al.  An integrated space-to-ground quantum communication network over 4,600 kilometres , 2021, Nature.

[5]  Marco Lucamarini,et al.  Coherent phase transfer for real-world twin-field quantum key distribution , 2020, Nature Communications.

[6]  Marco Lucamarini,et al.  600-km repeater-like quantum communications with dual-band stabilization , 2020, Nature Photonics.

[7]  Xiongfeng Ma,et al.  Implementation of quantum key distribution surpassing the linear rate-transmittance bound , 2020, Nature Photonics.

[8]  Zong-Wen Yu,et al.  Zigzag approach to higher key rate of sending-or-not-sending twin field quantum key distribution with finite-key effects , 2019, New Journal of Physics.

[9]  Marco Lucamarini,et al.  Experimental quantum key distribution beyond the repeaterless secret key capacity , 2019, Nature Photonics.

[10]  Zheng-Wei Zhou,et al.  Twin-field quantum key distribution over 830-km fibre , 2019, Nature Photonics.

[11]  Hai Xu,et al.  Sending-or-not-sending twin-field quantum key distribution in practice , 2018, Scientific Reports.

[12]  J. F. Dynes,et al.  Overcoming the rate–distance limit of quantum key distribution without quantum repeaters , 2018, Nature.

[13]  Hao Li,et al.  Fiber-coupled superconducting nanowire single-photon detectors integrated with a bandpass filter on the fiber end-face , 2018 .

[14]  L. Zhang,et al.  NbN superconducting nanowire single photon detector with efficiency over 90% at 1550 nm wavelength operational at compact cryocooler temperature , 2016, Science China Physics, Mechanics & Astronomy.

[15]  L. Banchi,et al.  Fundamental limits of repeaterless quantum communications , 2015, Nature Communications.

[16]  Nicolas Gisin,et al.  How far can one send a photon? , 2015, 1508.00351.

[17]  W. Wootters,et al.  A single quantum cannot be cloned , 1982, Nature.

[18]  H. Chernoff.  A Measure of Asymptotic Efficiency for Tests of a Hypothesis Based on the sum of Observations , 1952 .

[19]  R. Pound,et al.  Electronic frequency stabilization of microwave oscillators. , 1946, The Review of scientific instruments.

[20]  Physical Review Letters 63 , 1989 .