Observation of Fermi-Pasta-Ulam Recurrence Induced by Breather Solitons in an Optical Microresonator

TL;DR

This paper reports the experimental and numerical observation of Fermi-Pasta-Ulam recurrence caused by breather solitons in a high-Q silicon nitride microresonator, highlighting complex spectral dynamics and symmetry breaking.

Contribution

First demonstration of Fermi-Pasta-Ulam recurrence induced by breather solitons in an optical microresonator with detailed numerical analysis.

Findings

Breather solitons can be excited at small pump phase detuning.

Asymmetric power spectrum evolution observed around the spectrum center.

Stimulated Raman scattering influences symmetry breaking in spectral evolution.

Abstract

We present, experimentally and numerically, the observation of Fermi-Pasta-Ulam recurrence induced by breather solitons in a high-Q SiN microresonator. Breather solitons can be excited by increasing the pump power at a relatively small pump phase detuning in microresonators. Out of phase power evolution is observed for groups of comb lines around the center of the spectrum compared to groups of lines in the spectral wings. The evolution of the power spectrum is not symmetric with respect to the spectrum center. Numerical simulations based on the generalized Lugiato-Lefever equation are in good agreement with the experimental results and unveil the role of stimulated Raman scattering in the symmetry breaking of the power spectrum evolution. Our results shows that optical microresonators can be exploited as a powerful platform for the exploration of soliton dynamics.