We study how the information of the beam path is related to the Hong–Ou–Mandel interference with two pulsed light sources. Through a simple model in which two photons in the form of pulses pass a beam splitter and are observed at two detectors, we investigate how, during the measurement process, information about the paths of the two photons can be erased. There are two ways to clear the information of the beam path, the first being that from the beginning, during the physical measurement process, the time information is not obtained. The other is after measuring the information, to erase the temporal information in the data analyzing process. We show that Hong–Ou–Mandel interference can be obtained only when the beam path information is cleared from the physical measurement process.

我们研究了光束路径的信息与两个脉冲光源对Hong-Ou-Mandel干涉的关系。通过一个简单的模型，其中两个脉冲形式的光子通过分束器并在两个检测器处观察到，我们研究了在测量过程中如何擦除有关两个光子路径的信息。有两种清除光路信息的方法，第一种是从一开始就在物理测量过程中无法获得时间信息。另一个是在测量信息之后，在数据分析过程中擦除时间信息。我们证明，只有从物理测量过程中清除了光路信息后，才能获得Hong-Ou-Mandel干涉。