Alqedra Mohammed K, Huang Chiao-Tzu, Yeung Edith, Chang Wen-Hao, Haffouz Sofiane, Poole Philip J, Dalacu Dan, Elshaari Ali W, Zwiller Val
Department of Applied Physics, KTH Royal Institute of Technology, Roslagstullsbacken 21, 10691 Stockholm, Sweden.
Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
Nano Lett. 2025 Jul 2;25(26):10321-10327. doi: 10.1021/acs.nanolett.5c01130. Epub 2025 Jun 2.
Entangled photon pairs at telecom wavelengths are essential for quantum communication, distributed computing, and quantum-enhanced sensing. The telecom O-band offers low chromatic dispersion and fiber loss, which is ideal for long-distance networks. Site-controlled nanowire quantum dots have emerged as a promising platform for generating single and entangled photons, offering high extraction efficiency and scalability. However, their operation has largely been restricted to the visible and first near-infrared (NIR-I) windows. Here, we demonstrate a bright source of entangled photon pairs in the telecom O-band based on site-controlled nanowire quantum dots. We measure a fine-structure splitting of 4.6 μeV, confirming suitability for high-fidelity polarization entanglement. Quantum-state tomography of the biexciton-exciton cascade reveals a maximum fidelity of 85.8 ± 1.1% to the Φ Bell state and a maximum concurrence of 75.1 ± 2.1%. This work establishes nanowire quantum dots as viable entangled photon sources at telecom, advancing scalable quantum technologies for fiber-based networks.
电信波长的纠缠光子对对于量子通信、分布式计算和量子增强传感至关重要。电信O波段具有低色散和低光纤损耗的特点，这对于长距离网络来说是理想的。位点控制的纳米线量子点已成为产生单光子和纠缠光子的一个有前景的平台，具有高提取效率和可扩展性。然而，它们的操作在很大程度上局限于可见光和第一近红外（NIR-I）窗口。在此，我们展示了一种基于位点控制的纳米线量子点的电信O波段明亮纠缠光子对源。我们测量到4.6 μeV的精细结构分裂，证实其适用于高保真度偏振纠缠。双激子-激子级联的量子态层析成像显示，与Φ贝尔态的最大保真度为85.8±1.1%，最大并发度为75.1±2.1%。这项工作确立了纳米线量子点作为电信领域可行的纠缠光子源，推动了基于光纤网络的可扩展量子技术的发展。
