Chip-integrated visible-telecom entangled photon pair source for quantum communication
Chip-integrated visible-telecom entangled photon pair source for quantum communication
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DOI：
10.1038/s41567-018-0394-3
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发表时间：
2019-04-01
期刊：
影响因子：
19.6
通讯作者：
Srinivasan, Kartik
中科院分区：
文献类型：
--
作者：
Lu, Xiyuan;Li, Qing;Srinivasan, Kartik
光子对源是量子纠缠和量子通信的基本构件。最近在硅光子学方面的研究证明，在电信频段内的光子对源具有良好的特性，包括亚毫瓦级的光泵浦功率、高光谱亮度和高光子纯度。然而，大多数适合于局域操作的量子系统，如存储和计算，都支持可见光或短近红外波段的光学跃迁。与电信波长相比，二氧化硅在这些波长下的较高光衰减限制了此类本地节点之间基于光纤的量子通信的长度范围。通过光纤连接这种系统的一种方法是通过可以连接可见光和电信频段的光子对源，但在综合平台中尚未开发出适当的源，该源应该产生具有高信噪比的窄带光子对。在这里，我们展示了一个纳米光子可见通信光子对源，使用高质量因子氮化硅谐振器产生了具有前所未有的纯度和亮度的窄带光子对，巧合与偶然比高达3,780+/-140，探测到的光子对通量高达(18,400+/-1,000)对S(-1)。我们进一步展示了可见光通信的时间-能量纠缠及其在20公里光纤上的分布，远远超过了纯可见光波长量子光源可以有效传输的光纤长度。最后，我们展示了微谐振器的色散工程如何使不同种类的捕获原子/离子、缺陷中心和量子点连接到未来量子通信系统的电信频段。
Photon pair sources are fundamental building blocks for quantum entanglement and quantum communication. Recent studies in silicon photonics have documented promising characteristics for photon pair sources within the telecommunications band, including sub-milliwatt optical pump power, high spectral brightness and high photon purity. However, most quantum systems suitable for local operations, such as storage and computation, support optical transitions in the visible or short near-infrared bands. In comparison to telecommunications wavelengths, the higher optical attenuation in silica at such wavelengths limits the length scale over which optical-fibre-based quantum communication between such local nodes can take place. One approach to connect such systems over fibre is through a photon pair source that can bridge the visible and telecom bands, but an appropriate source, which should produce narrow-band photon pairs with a high signal-to-noise ratio, has not yet been developed in an integrated platform. Here, we demonstrate a nanophotonic visible-telecom photon pair source, using high quality factor silicon nitride resonators to generate narrow-band photon pairs with unprecedented purity and brightness, with a coincidenceto-accidental ratio up to 3,780 +/- 140 and a detected photon pair flux up to (18,400 +/- 1,000) pairs s(-1). We further demonstrate visible-telecom time-energy entanglement and its distribution over a 20 km fibre, far exceeding the fibre length over which purely visible wavelength quantum light sources can be efficiently transmitted. Finally, we show how dispersion engineering of the microresonators enables the connections of different species of trapped atoms/ions, defect centres and quantum dots to the telecommunications bands for future quantum communication systems.