Bifunctional acoustic lossy coupler for broadband power splitting and absorption

In this work, we propose a bifunctional acoustic lossy coupler for broadband power splitting and absorption. Following the three-level system in quantum physics, the three-waveguide (WG) acoustic system is proposed to obtain efficient energy transfer behaviors. Given the agreement in form between Schr $\ddot{o}$ dinger equation and coupled mode equation, the time-dependent external fields are mapped into space-varying coupling actions between adjacent WGs. The propagation paths of the incident waves can be predicted by Schr $\ddot{o}$ dinger-like equation, which are verified by numerical simulations and experimental measurements. Owing to the different responses to lossy medium in WG B for WG A incidence and WG C incidence, the acoustic coupler can be considered as a broadband power splitter and muffler by selecting different input ports. Meanwhile, according to the reversibility of acoustic path, a switchable acoustic logic gate with functions of “OR” and “XOR” is constructed as well by taking advantage of the lossless adiabatic coupler, and the function can be controlled conveniently by reversing the phase of input waves from WG A or C. Our work provides a new scheme for the design of bifunctional acoustic coupler, which may have a profound impact on the development of non-resonance acoustic high-performance devices.