High fidelity entanglement swapping at telecommunication wavelength using single-photon detectors based on compound semiconductors

利用空间分离的偏振纠缠光子源在1550 nm处进行了纠缠交换实验。在本实验中，我们使用了正弦选通的InGaAs/InP雪崩光电二极管，实现了高重复频率和低暗计数。高性能的单光子探测器使我们能够获得约0.9的纠缠交换保真度。高保真纠缠交换将能够应用于光纤网络上的量子密钥分配。

Entanglement swapping experiment was carried out using spatially separated, polarization entangled photon sources at 1550 nm. In this experiment, we employed sinusoidally gated InGaAs/InP avalanche photodiodes which achieve high repetition frequencies and low dark counts. The high-performance single-photon detectors enable us to obtain ~ 0.9 of a fidelity of the entanglement swapping. The high-fidelity entanglement swapping will be able to be applied to the quantum key distribution over an optical fiber network.