Center for Telecommunication Studies, Pontifical Catholic University of Rio de Janeiro, R. Marquês de São Vicente 225, Gávea, 22451-900, Rio de Janeiro, Brazil.
Opt Lett. 2011 May 15;36(10):1764-6. doi: 10.1364/OL.36.001764.
We experimentally demonstrate stable and user-adjustable single-photon interference in a 1 km long fiber-optic Mach-Zehnder interferometer, using an active phase control system with the feedback provided by a classical laser. We are able to continuously tune the single-photon phase difference between the interferometer arms using a phase modulator, which is synchronized with the gate window of the single-photon detectors. The phase control system employs a piezoelectric fiber stretcher to stabilize the phase drift in the interferometer. A single-photon net visibility of 0.97 is obtained, yielding future possibilities for experimental realizations of quantum repeaters in optical fibers and violation of Bell's inequalities using genuine energy-time entanglement.
我们在 1 公里长的光纤马赫-曾德尔干涉仪中实验演示了稳定且用户可调的单光子干涉，该干涉仪采用了带有经典激光反馈的主动相位控制系统。我们能够使用相位调制器连续调节干涉仪臂之间的单光子相位差，该相位调制器与单光子探测器的门控窗口同步。相位控制系统采用了压电光纤拉伸器来稳定干涉仪中的相位漂移。我们得到了 0.97 的单光子网络可见度，这为在光纤中实现量子中继器以及使用真正的能量-时间纠缠违反贝尔不等式的实验实现提供了未来的可能性。
