Reconfigurable nano-scale spin-wave directional coupler

TL;DR

This paper introduces a reconfigurable nano-scale spin-wave directional coupler that uses dipolar coupling between waveguides, enabling dynamic control of energy transfer for applications in magnonics and microwave signal processing.

Contribution

It proposes a novel reconfigurable spin-wave coupler design based on dipolar coupling, with tunable energy transfer properties controlled by frequency, magnetic field, and magnetization orientation.

Findings

Coupling length depends on dipolar interaction and can be tuned.

Energy transfer can be controlled by external parameters.

Device can function as a multiplexer or power divider.

Abstract

A spin-wave (SW) directional coupler comprised of two laterally parallel nano-scale dipolarly-coupled SW waveguides is proposed and studied using micromagnetic simulations and analytical theory. The energy of a SW excited in one of the waveguides in the course of propagation is periodically transferred to the other waveguide and back, and the spatial half-period of this transfer is defined as the coupling length. The coupling length is determined by the dipolar coupling between the waveguides, and the fraction of the SW energy transferred to the other waveguide at the device output can be varied with the SW frequency, bias magnetic field, and relative orientation of the waveguide's static magnetizations. The proposed design of a directional coupler can be used in digital computing-oriented magnonics as a connector (multiplexer) of magnonic conduits without a direct contact, or in the analog microwave signal processing as a reconfigurable nano-scale power divider and/or frequency separator.