利用超高纯度单光子源和超导单光子探测器实现120公里的量子密钥分发。
Quantum key distribution over 120 km using ultrahigh purity single-photon source and superconducting single-photon detectors.
作者信息
Takemoto Kazuya, Nambu Yoshihiro, Miyazawa Toshiyuki, Sakuma Yoshiki, Yamamoto Tsuyoshi, Yorozu Shinichi, Arakawa Yasuhiko
机构信息
Devices &Materials Laboratory, Fujitsu Laboratories Ltd., 10-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0197, Japan.
Smart Energy Research Laboratories, NEC Corporation, 34 Miyukigaoka, Tsukuba, Ibaraki 305-8501, Japan.
出版信息
Sci Rep. 2015 Sep 25;5:14383. doi: 10.1038/srep14383.
Advances in single-photon sources (SPSs) and single-photon detectors (SPDs) promise unique applications in the field of quantum information technology. In this paper, we report long-distance quantum key distribution (QKD) by using state-of-the-art devices: a quantum-dot SPS (QD SPS) emitting a photon in the telecom band of 1.5 μm and a superconducting nanowire SPD (SNSPD). At the distance of 100 km, we obtained the maximal secure key rate of 27.6 bps without using decoy states, which is at least threefold larger than the rate obtained in the previously reported 50-km-long QKD experiment. We also succeeded in transmitting secure keys at the rate of 0.307 bps over 120 km. This is the longest QKD distance yet reported by using known true SPSs. The ultralow multiphoton emissions of our SPS and ultralow dark count of the SNSPD contributed to this result. The experimental results demonstrate the potential applicability of QD SPSs to practical telecom QKD networks.
单光子源（SPSs）和单光子探测器（SPDs）的进展有望在量子信息技术领域实现独特的应用。在本文中，我们报告了使用最先进的设备进行的长距离量子密钥分发（QKD）：一个在1.5μm电信波段发射光子的量子点单光子源（QD SPS）和一个超导纳米线单光子探测器（SNSPD）。在100公里的距离上，我们在不使用诱骗态的情况下获得了27.6比特每秒的最大安全密钥率，这至少比之前报道的50公里长的QKD实验中获得的速率大三倍。我们还成功地在120公里的距离上以0.307比特每秒的速率传输了安全密钥。这是使用已知真正单光子源报道的最长QKD距离。我们的单光子源的超低多光子发射和超导纳米线单光子探测器的超低暗计数促成了这一结果。实验结果证明了量子点单光子源在实际电信QKD网络中的潜在适用性。
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