Eur. Phys. J. D (2017) 71: 74
https://doi.org/10.1140/epjd/e2017-70705-x

Regular Article

Coupled Lugiato-Lefever equation for nonlinear frequency comb generation at an avoided crossing of a microresonator^*

¹ Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, 78712 Texas, USA
² Department of Computer Science and Electrical Engineering, University of Maryland, 1000 Hilltop Circle, Baltimore, 21250 Maryland, USA

^a e-mail: giuseppe.daguanno@gmail.com

Received: 12 November 2016
Received in final form: 16 February 2017
Published online: 23 March 2017

Abstract

Guided-mode coupling in a microresonator generally manifests itself through avoided crossings of the corresponding resonances. This coupling can strongly modify the resonator local effective dispersion by creating two branches that have dispersions of opposite sign in spectral regions that would otherwise be characterized by either positive (normal) or negative (anomalous) dispersion. In this paper, we study, both analytically and computationally, the general properties of nonlinear frequency comb generation at an avoided crossing using the coupled Lugiato-Lefever equation. In particular, we find that bright solitons and broadband frequency combs can be excited when both branches are pumped for a suitable choice of the pump powers and the detuning parameters. A deterministic path for soliton generation is found.