Stable dark and bright soliton Kerr combs can coexist in normal dispersion resonators

TL;DR

This paper demonstrates that third order dispersion enables stable coexistence of dark and bright solitons in normal dispersion Kerr resonators, expanding the understanding of soliton dynamics in optical frequency combs.

Contribution

It reveals that third order dispersion allows for stable coexistence of dark and bright solitons, which was not possible without it, and analyzes their stability and switching behaviors.

Findings

Third order dispersion enables coexistence of dark and bright solitons.

Reversibility is broken and switching wave shapes are altered.

Oscillatory instabilities of dark solitons are suppressed.

Abstract

Using the Lugiato-Lefever model, we analyze the effects of third order chromatic dispersion on the existence and stability of dark and bright soliton Kerr frequency combs in the normal dispersion regime. While in the absence of third order dispersion only dark solitons exist over an extended parameter range, we find that third order dispersion allows for stable dark and bright solitons to coexist. Reversibility is broken and the shape of the switching waves connecting the top and bottom homogeneous solutions is modified. Bright solitons come into existence thanks to the generation of oscillations in the switching wave profiles. Finally, oscillatory instabilities of dark solitons are also suppressed in the presence of sufficiently strong third order dispersion.