By using a fiber loop with a phase modulator, we simulate the refraction and reflection effects of optical pulses at the heterointerface in the time domain, which is formed by abruptly varying the modulation depth or frequency. When the variation is periodically imposed on the optical pulse, the heterointerface is vertical and may lead to total internal reflection. The temporal refraction can be controlled by setting different Bloch wave vectors at incidence. As the variation occurs at a specific moment during the pulse propagation, a horizontal interface appears, and the negative refraction and pulse splitting in the time domain could be observed. We also show that the combination between the straight and tilted lattice could provide another way to control the temporal refraction. The study may find great applications in signals processing and optical communication.

中文翻译：

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时间晶格异质结构中的离散折射和反射

通过使用带有相位调制器的光纤环路，我们可以在时域中模拟光脉冲在异质界面上的折射和反射效应，这是通过突然改变调制深度或频率而形成的。当变化周期性地施加在光脉冲上时，异质界面是垂直的，并可能导致全内反射。可以通过在入射时设置不同的布洛赫波矢量来控制时间折射。由于变化发生在脉冲传播的特定时刻，因此出现了水平界面，并且可以观察到时域中的负折射和脉冲分裂。我们还表明，直线晶格和倾斜晶格之间的组合可以提供另一种方式来控制时间折射。