近日，中国科学院物理研究所陆凌团队研究了具有100dB隔离的拓扑微波隔离器。相关论文于2025年9月16日发表在《自然—光子学》杂志上。

微波隔离器在第二次世界大战后发展起来，是必不可少的非互反设备，广泛用于尽量减少各种应用的信号反射和干扰，包括移动基站，卫星通信，雷达系统，磁共振成像和工业微波加热。一个典型的商用微波隔离器提供20dB的隔离，减少了两个数量级的反向功率。虽然对于需要更大功率或更低噪声的系统，例如超导量子计算，总是需要更高的隔离，但在传统设计中，向后信号的进一步减少将不可避免地导致前向传输的不可接受的退化。

研究组介绍了拓扑隔离器的原理，它基于一个独特的单向边缘波导，在空间上分离正向和反向波，可完全吸收反向传播模式，而不影响任何正向信号。这种理想的隔离机制产生了前所未有的隔离水平，分析得出在单个波长尺寸的器件内为200dB。它仅受到铁氧体材料拓扑带隙内的倏逝场的限制，该带隙跨越两个八度，约为10GHz。

研究组通过实验证明了这种拓扑隔离器在带状线配置下的最小插入损耗为1dB和反向信号深度衰减到仪器噪声底。这导致超高隔离度超过100dB，比传统隔离度提高了8个数量级。该工作不仅为上述技术中的高性能隔离器铺平了道路，而且为各种相关微波元件的创新奠定了基础。

附：英文原文

Title: Topological microwave isolator with >100-dB isolation

Author: Wang, Gang, Lu, Ling

Issue&Volume: 2025-09-16

Abstract: Microwave isolators, developed after World War II, are essential non-reciprocal devices widely used to minimize signal reflections and interference across various applications, including mobile base stations, satellite communications, radar systems, magnetic resonance imaging and industrial microwave heating. A typical commercial microwave isolator provides 20dB of isolation, reducing the backward power by two orders of magnitude. Although higher isolation is always desired for systems that require greater power or lower noise, such as superconducting quantum computing, further reduction in the backward signal will inevitably lead to an unacceptable degradation in the forward transmission in traditional designs. Here we introduce the principle of a topological isolator, based on a unique one-way edge waveguide that spatially separates forward and backward waves, allowing for the complete absorption of the backward-propagating mode without compromising any forward signal. This ideal isolation mechanism produces an unprecedented isolation level, analytically derived to be 200dB within a single-wavelength-size device. It is limited only by the evanescent fields within the topological bandgap in the ferrite material that spans two octaves around 10GHz. We experimentally demonstrate this topological isolator in a stripline configuration with a minimal insertion loss of 1dB and a backward signal deeply attenuated to the instrument noise floor. This results in an ultrahigh isolation exceeding 100dB—an eight-orders-of-magnitude improvement over conventional counterparts. Our work not only paves the way for higher-performance isolators in the aforementioned technologies but also sets the stage for innovation in a variety of related microwave components.

DOI: 10.1038/s41566-025-01750-w

Source: https://www.nature.com/articles/s41566-025-01750-w