Many photonic quantum information processing applications would benefit from a high brightness, fiber-coupled source of triggered single photons. Here, we present a fiber-coupled photonic-crystal waveguide single-photon source relying on evanescent coupling of the light field from a tapered out-coupler to an optical fiber. A two-step approach is taken where the performance of the tapered out-coupler is recorded first on an independent device containing an on-chip reflector. Reflection measurements establish that the chip-to-fiber coupling efficiency exceeds 80 %. The detailed characterization of a high-efficiency photonic-crystal waveguide extended with a tapered out-coupling section is then performed. The corresponding overall single-photon source efficiency is 10.9 % ± 2.3 %, which quantifies the success probability to prepare an exciton in the quantum dot, couple it out as a photon in the waveguide, and subsequently transfer it to the fiber. The applied out-coupling method is robust, stable over time, and broadband over several tens of nanometers, which makes it a highly promising pathway to increase the efficiency and reliability of planar chip-based single-photon sources.

中文翻译：

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基于光子晶体波导中的量子点的高效光纤耦合单光子源。

许多光子量子信息处理应用将受益于高亮度、光纤耦合的触发单光子源。在这里，我们提出了一种光纤耦合光子晶体波导单光子源，它依赖于光场从锥形输出耦合器到光纤的渐逝耦合。采用两步方法，首先在包含片上反射器的独立设备上记录锥形输出耦合器的性能。反射测量表明芯片到光纤的耦合效率超过 80%。然后对延伸有锥形输出耦合部分的高效光子晶体波导进行详细表征。相应的整体单光子源效率为10.9%±2.3%，它量化了在量子点中制备激子、将其作为波导中的光子耦合出来、随后将其传输到光纤的成功概率。所应用的输出耦合方法具有鲁棒性、随时间稳定且宽带超过数十纳米的特点，这使其成为提高基于平面芯片的单光子源的效率和可靠性的非常有前景的途径。