中文摘要：

在一个磅对称的系统控制平衡获得和损失是一项相当挑战性的任务。利用 Floquet 理论，我们在控制磅对称的光 coupler 的获得和损失探索周期的调整的建设性的角色。系统的获得和损失能被使用周期的调整操作，这被发现。进一步，如此的一个原来的 non-Hermitian 系统能甚至被调制进高周波的 Floquet 方法导出的一个有效 Hermitian 系统。与另外的磅对称控制计划相比，因此，我们的协议能调制未破损的磅对称的范围到一个更宽的参数区域。我们的结果为控制一个现实主义的系统的获得和损失提供一条有希望的途径。

英文摘要：

Controlling the balanced gain and loss in a PT-symmetric system is a rather challenging task. Utilizing Floquet theory, we explore the constructive role of periodic modulation in controlling the gain and loss of a PT-symmetric optical coupler. It is found that the gain and loss of the system can be manipulated by applying a periodic modulation. Purther, such an original non-Hermitian system can even be modulated into an effective Hermitian system derived by the high-frequency Floquet method. Therefore, compared with other PT- symmetry control schemes, our protocol can modulate the unbroken PT-symmetric range to a wider parameter region. Our results provide a promising approach for controlling the gain and loss of a realistic system.