Microresonator dynamics with frequency-dependent Kerr nonlinearity

We investigate the ultrafast nonlinear dynamics in a silica ringresonator composed of a silver-nanoparticledoped core that exhibits rapidly varying frequency-dependent Kerr nonlinearity that even changes sign across a specific frequency, defined as zero-nonlinearity frequency. We model optical propagation in such a resonator through a modified Lugiato-Lefever equation, revealing that the formation of bright cavity solitons can be possible in both positive and negative nonlinearity domains. The intrapulse Raman scattering along with the frequency-dependent Kerr nonlinearity modify the stability and the dynamics of cavity solitons, which we analyze using a bistability analysis, intracavity modulation-instability analysis, and semianalytical variational approach. Our derived analytical results agree well with the direct numerical solutions of the Lugiato-Lefever equation. The generation of a dispersive wave from a cavity soliton encountering higher-order dispersion is also influenced by the location of the zero-nonlinearity frequency, which we describe by providing a modified phase matching equation. Our results and analysis provide a framework for better understanding the dynamics of cavity solitons and their interactions in two different bright-solitonic domains with possible applications in dual-pump spectroscopy, formation of soliton molecules, and counterpropagating solitons to other fields.

Automated summary

Our study investigates ultrafast nonlinear dynamics in a silica ring resonator with a silver-nanoparticle-doped core, revealing rapidly varying frequency-dependent Kerr nonlinearity and the possibility of forming bright cavity solitons in both positive and negative nonlinearity domains. The dynamics of cavity solitons are modified by intrapulse Raman scattering and frequency-dependent Kerr nonlinearity, influenced by the location of the zero-nonlinearity frequency. The results provide insights into the interactions of cavity solitons in different bright-solitonic domains, with potential applications in dual-pump spectroscopy and formation of soliton molecules.