随着量子信息技术的发展，对量子光学器件的研究越来越受到重视。其中构建可以实现非互易传输的量子器件在量子信息中起着重要作用。本文对具有莫比乌斯环结构的量子器件进行了研究，并利用其拓扑性质实现了非互易传输。在此方案中，我们使用二能级腔组合成的莫比乌斯双环阵列，在环上选取两个节点连接一维半无限长链，通过格林函数方法计算通过莫比乌斯环上能带的透射率。当选取偏离对称点的一对连接节点时，就会在上能带出现明显的非互易透射。与其它非互易量子器件相比，我们的方案案在 单激发条件下即可实现。此外，通过调节参数和修改结构能够优化透射谱的非互异性。 因此，本方案兼具被动性与单激发。具体内容由以下几点构成：

1.莫比乌斯环的能带结构。本文在前人研究的基础上利用拓扑结构的性质，使用傅里 叶变换得到莫比乌斯环型耦合腔阵列的能带结构。其中上能带关于k = 0 不对称，这启发 我们利用莫比乌斯环上能带实现非互易器件。

2.非互易的透射谱。当波导连接至环上的非对称节点时，就能观察到上能带的透射 谱是非互易的。但在共振点上依然保持光子阻塞。特别地，奇数N的k = − N−1 N π共振点上 的光子阻塞消失了。我们研究了参数对该共振点上非互易性的影响，发现N越小，在参 数κ空间能产生明显非互易的区间越大。

3.共振点光子阻塞的消除。我们在环上的某一节点附加二能级系统来消除共振点上的 光子阻塞。具体地，使各种环的a+,3号腔与一个二能级原子耦合，得到在共振点上的光子 阻塞或消失或移动了位置。

With the development of quantum information technology, more and more attention has been paid to the research of quantum optical devices. The quantum devices which can realize nonreciprocal transmission plays an important role in quantum information. In this paper, the quantum devices with Mobius ring structure are theoretically studied, and the nonreciprocal transmission is realized by using their topological properties. In this scheme, we use the Mobius double ring array composed of two-level cavities, select two nodes on the ring to connect the one-dimensional semiinfinite chains, and calculate the transmission through the up band of the Mobius ring by using the Green function method. When a pair of connected nodes deviating from the symmetrical point are selected, there will be obvious nonreciprocal transmission through the up band. Compared with other nonreciprocal quantum devices, our scheme can be realized under the condition of single excitation. In addition, by adjusting the parameters and modifying the structure, the transmission spectrum can be optimized. Therefore, this scheme has both passivity and single excitation. The specific content consists of the following:

1. Energy band structure of the Mobius ring. On the basis of previous studies, we use the properties of topological structure and the Fourier transform to obtain the band structure of coupled cavity array in type of Mobius ring. Where the up band is about k = 0 asymmetric, which inspired us to use this band of Mobius ring to realize nonreciprocal devices.

2. Nonreciprocal transmission spectrum. When the waveguide is connected to the asymmetric node on the ring, it can be observed that the transmission spectrum of the up band is nonreciprocal. But at the resonance points, there is still photon blockade. Specifically, ring of odd N has lost the photon blockade at the resonance point k = − N−1 N π. We have studied the influence of parameters to the nonreciprocity at this resonance point, and found that the smaller the N is, the larger the regime of significant nonreciprocity can be generated in the parameter κ space.

3. Elimination of photon blockade at resonance point. We attach a two-level system to a node in the ring to eliminate the photon blockade at the resonance point. Specifically, by coupling the a+,3 cavities of various rings with a two-level atom, we can get the position of photon blockade disappearing or moving at the resonance point.