Research Article

Interplay of χ⁽²⁾ and χ⁽³⁾ effects for microcomb generation

¹ Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120 Palaiseau, France
² Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Cité, 75013 Paris, France
³ Institute of Photonics and Quantum Electronics, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
⁴ Department of Chemistry and Physics, University of Almeria, 04120 Almeria, Spain
⁵ Department of Physics, Chemistry and Biology, Linköping University, Linköping, SE-581 83, Sweden
⁶ Service OPERA-Photonique, Université libre de Bruxelles, B-1050 Brussels, Belgium
⁷ Dipartimento di ingegneria elettronica e telecomunicazioni, Sapienza University of Rome, 00184 Roma, Italy
⁸ CNR-INO, Istituto Nazionale di Ottica, 80078 Pozzuoli, Italy

^* Corresponding author: francesco-rinaldo.talenti@universite-paris-saclay.fr

Received: 29 January 2025
Accepted: 7 April 2025

Abstract

While frequency comb generation in passive nonlinear optical cavities has been demonstrated in purely quadratic and Kerr platforms, the interplay between χ⁽²⁾ and χ⁽³⁾ effects is yet to be fully understood. In this work, we propose a doubly resonant AlGaAs microring design for second-harmonic Kerr-comb generation. We compute the full dispersion profile of the guided modes to describe the resulting dynamics. The doubly resonant condition implies the use of a double envelope mean-field model, and the confined field owns spectral components around both the pump and second harmonic wavelengths. The fabrication of such devices is discussed, and preliminary experimental results are presented. Due to its record nonlinear performance, we address AlGaAs as a promising platform for the generation of such novel microcomb sources.