We propose an effective approach for creating robust nonreciprocity of high-order sidebands, including the first-, second-, and third-order sidebands, at microwave frequencies. This approach relies on magnon Kerr nonlinearity in a cavity magnonics system composed of two microwave cavities and one yttrium iron garnet (YIG) sphere. By manipulating the driving power applied on YIG and the frequency detuning between the magnon mode in YIG and the driving field, the effective Kerr nonlinearity can be strengthened, thereby inducing strong transmission nonreciprocity. More interestingly, we find the higher the sideband order, the stronger the transmission nonreciprocity marked by the higher isolation ratio in the optimal detuning regime. Such a series of equally spaced high-order sidebands have potential applications in frequency comblike precision measurement, besides structuring high-performance on-chip nonreciprocal devices.

中文翻译：

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由 magnon Kerr 非线性引起的非互易高阶边带

我们提出了一种在微波频率下创建高阶边带（包括一阶、二阶和三阶边带）的稳健非互易性的有效方法。这种方法依赖于由两个微波腔和一个钇铁石榴石 (YIG) 球组成的腔磁系统中的磁振子克尔非线性。通过操纵施加在 YIG 上的驱动功率和 YIG 中的磁振子模式与驱动场之间的频率失谐，可以加强有效的克尔非线性，从而诱导强传输非互易性。更有趣的是，我们发现边带阶数越高，传输非互易性越强，以最佳失谐状态中更高的隔离比为标志。