Artificial discovery of lattice models for wave transport

TL;DR

This paper introduces an automated method for designing lattice models that achieve specific wave transport functionalities, significantly accelerating the discovery process for devices like amplifiers and isolators.

Contribution

It presents a novel optimization approach combined with symbolic regression to systematically discover simple lattice models with desired wave transport properties.

Findings

Identified new lattice schemes for directional amplifiers and isolators.

Derived analytical expressions for generalizable design rules.

Demonstrated applicability across microwave, optical, and optomechanical systems.

Abstract

Wave transport devices, such as amplifiers, frequency converters, and nonreciprocal devices, are essential for modern communication, signal processing, and sensing applications. Of particular interest are traveling wave setups, which offer excellent gain and bandwidth properties. So far, the conceptual design of those devices has relied on human ingenuity. This makes it difficult and time-consuming to explore the full design space under a variety of constraints and target functionalities. In our work, we present a method which automates this challenge. By optimizing the discrete and continuous parameters of periodic coupled-mode lattices, our approach identifies the simplest lattices that achieve the target transport functionality, and we apply it to discover new schemes for directional amplifiers, isolators, and frequency demultiplexers. Leveraging automated symbolic regression tools, we find closed analytical expressions that facilitate the discovery of generalizable construction rules. Moreover, we utilize important conceptual connections between the device transport properties and non-Hermitian topology. The resulting structures can be implemented on a variety of platforms, including microwave, optical, and optomechanical systems. Our approach opens the door to extensions like the artificial discovery of lattice models with desired properties in higher dimensions or with nonlinear interactions.