# Temporal quadratic solitons and their interaction with dispersive waves in Lithium Niobate nano-waveguides

## TL;DR

This paper models quadratic soliton propagation in lithium niobate nano-waveguides, develops existence criteria, and demonstrates through simulations the generation and interaction of solitons, dispersive waves, and quasi-solitons at accessible powers.

## Contribution

It introduces a new model for quadratic solitons in nano-waveguides, identifies five regimes of soliton existence, and confirms soliton generation through simulations at practical power levels.

## Key findings

- Five regimes of soliton and quasi-soliton existence identified.
- Soliton generation confirmed at experimentally accessible powers.
- Interactions between quadratic solitons and dispersive waves analyzed and predicted.

## Abstract

We present a model of soliton propagation in waveguides with quadratic nonlinearity. Criteria for solitons to exist in such waveguides are developed and two example nano-waveguide structures are simulated as proof of concept. Interactions between quadratic solitons and dispersive waves are analysed giving predictions closely matching soliton propagation simulations. The example structures are found to support five different regimes of soliton and quasi-soliton existence. Pulse propagation in these example waveguides has been simulated confirming the possibility of soliton generation at experimentally accessible powers. Simulations of multi-soliton generation, Cherenkov radiation and quasi-solitons with opposite signs of dispersion in the fundamental and second harmonic are also presented here.