Optimizing the coupling efficiency of spontaneous parametric down-conversion photon pairs into single-mode fibers
Optimizing the coupling efficiency of spontaneous parametric down-conversion photon pairs into single-mode fibers
复制标题
优化自发参量下转换光子对与单模光纤的耦合效率
DOI：
10.1103/physreva.106.043719
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发表时间：
2022
影响因子：
2.9
通讯作者：
Takeuchi Shigeki
中科院分区：
文献类型：
--
作者：
Schwaller Nicolas;Park Geobae;Okamoto Ryo;Takeuchi Shigeki
耦合到单模光纤中的自发参量下转换（SPDC）的相关模耦合效率和光子对通量（亮度）是各种量子信息科学应用的关键参数。我们提出了一个实验研究的相关模式耦合效率和亮度的频率简并的SPDC光子对进入单模光纤的优化。利用连续激光泵浦的I型相位匹配块体硼酸钡晶体产生的光子对，我们仔细评估了耦合到单模光纤的相关模耦合效率和SPDC光的亮度，同时连续改变泵浦和收集模式的聚焦，用瑞利长度为晶体长度的3至280倍（对于泵浦）和0.2至20倍（对于收集）进行实验。测量数据表明，对于任何泵浦焦点，相关模耦合效率都接近于1，然而，收集模的最佳瑞利长度取决于泵浦焦点参数，如果精确调节收集模的瑞利长度，则可以通过收紧泵浦焦点来增加亮度。实验测得相关模耦合效率最高为。这些结果将有助于利用高效率的SPDC光源的光子量子科学和技术。
Both correlated-mode coupling efficiency and photon pair flux (brightness) of spontaneous parametric down-conversion (SPDC) coupled into single-mode fibers are key parameters for various quantum information science applications. We present an experimental investigation on the optimization of the correlated-mode coupling efficiency and the brightness of frequency-degenerated SPDC photon pairs into single-mode optical fibers. Using photon pairs generated from a type-I phase-matched bulk-barium borate crystal pumped by a continuous-wave laser, we carefully evaluated both the correlated-mode coupling efficiency and the brightness of SPDC light coupled to a single-mode optical fiber, while continuously changing the focusing of the pump and collection modes, experimenting with Rayleigh lengths from 3 to 280 (for the pump) and 0.2 to 20 (for the collection) times the crystal length. The measured data suggest that the correlated-mode coupling efficiency can be close to unity for any pump focus, however, the optimal Rayleigh length of the collection mode depends on the pump focus parameter, and the brightness can be increased by tightening the pump focus, provided that the Rayleigh length of the collection mode is precisely adjusted. A maximal correlated-mode coupling efficiency ofwas experimentally achieved. These results will be useful for photonic quantum science and technology using SPDC sources with high heralding efficiencies.