A MEMS Topological Coupler with Tunable-Transfer Coefficient by frequency

A study conducted by Keita Funayama et al. was published in ADVANCED SCIENCE.

Topological waveguides have a great potential to realize high-efficient and unidirectional energy/signal transmissions. Topological integrated circuit system is one of the ideals topological applications. To construct such topological integrated systems, functional circuits elements enabling signal transfer and processing have been required with keeping topological nature. However, the wave characteristics in topological waveguides are difficult to actively control via external interferences because of their robustness, resulting in remained challenges for functionalizing topological circuits elements. In this study, we demonstrate the transfer coefficient-tunable topological coupler by frequency. This functional topological element consists of adjacent two bridge boundaries based on the quantum valley Hall showing frequency-dependent wave localization in the topological waveguides. The coupling strength between the adjacent waveguides can be finely controlled by the variable wave localization. Further topologically protected digital signal transfer is demonstrated with frequency shift keying modulation in the topological coupler, revealing the data-transfer capability close to the theoretical limit. Our results open up the door toward the development of fundamental building blocks for topological integrated systems.

An illustration from this study was selected as one of the covers of the journal covers.
https://advanced.onlinelibrary.wiley.com/toc/21983844/2025/12/35

Title: Quantum Valley Hall Effect-Based Coupler with Continuously Tunable Transmission for Topological Information Communication
Authors: Funayama, K., Yatsugi, K., Tanaka, H., Iizuka, H.
Journal Name: ADVANCED SCIENCE
Published: June 29, 2025
https://doi.org/10.1002/advs.202506732