All-fiber frequency agile triple-frequency comb light source

The ANR FARCO project (2022-2024), spearheaded by the Photonics team, is an ambitious initiative targeting the development of groundbreaking technology in both linear and nonlinear spectroscopy. This project is founded on the innovation of a new category of versatile and scalable all-fiber, powerful multi-frequency comb laser sources (both dual and tri-frequency) that facilitate the simultaneous utilization of multiple combs while ensuring high mutual coherence and a compact design.

The aim is to demonstrate that this technology can significantly enhance analysis speed and precision by several orders of magnitude in nonlinear spectroscopy.  This project is poised to lay the groundwork for advanced mutidimensionnal coherent spectroscopy for measuring decoherence dynamics across a wide array of material systems, including cold atoms, gases, and semiconductors. The goal is to uncover universal principles governing many-body interactions and to facilitate real-time tracking of chemical reactions, among other applications.


The initial major achievement of the project is the successful demonstration of a proof of concept for multidimensional coherent spectroscopy. We have shown that the three-comb system can coherently interact (i) to generate a nonlinear signal that encapsulates the information required for analysis from a sample, and (ii) by utilizing a third comb as a local sampling oscillator for the analysis of this nonlinear signal. This innovative approach paves the way for the efficient extraction and rapid analysis of complex information from samples, marking a significant advancement in the field of spectroscopy.

Top left: An image depicting the three-core fiber, showcasing its unique structure designed for advanced light manipulation. Bottom left: A spectrum illustrating the coherent beating between two combs, with a subsequent down-conversion into the radio frequency domain. This visualization captures the intricate interactions and the coherent dynamics of the combs. Right: A nonlinear spectrum in the radio frequency domain plotted as a function of the pump-probe delay. This two-dimensional plot serves as a proof of concept for Multidimensional Coherent



[1] Bancel, EL., Genier, E., Santagata, R. et al. All-fiber frequency agile triple-frequency comb light source. Nat Commun 14, 7953 (2023)

[2] Eve-Line Bancel, Rosa Santagata, Matteo Conforti, and Arnaud Mussot, "Intra-envelope four-wave mixing in optical fibers," Opt. Express 31, 37645-37652 (2023)

[3] Peignes de fréquence triples pour source laser entièrement fibrée | journal du CNRS 2024.