Electro-optic Frequency Combs

This is the topic I studied during my PhD entitled Frequency comb generation by electro-optic modulation and applications. The aim was to develop dual-comb spectrometers based on the electro-optic modulation of a continuous wave laser and to perform spectroscopy with it. This topic was closely linked to the use of optical fibers and nonlinear optics to frequency convert the center wavelength of the combs in a suitable spectral region for spectroscopic applications (see here for more information on nonlinear optics in fibers).

On this topic, I published a review article in Advances in optics and photonics [AOP-20], which is well cited (~400 in 6 years), and a book chapter [OFC-24].

Frequency conversion in the mid-infrared

The last work I performed during my PhD was to extend the spectral region analysis of the dual-comb spectrometer in the mid-infrared to perform isotope ratio measurements [PRR-22]. For this, I implemented a difference frequency generation setup to reach the spectral region around 4.5 µm. With this setup, I performed the first demonstration of isotope ratio measurements with a dual-comb setup.

Figure: Absorption spectrum of nitrous oxide recorded with a mid-infrared dual-comb spectrometer based on electro-optic modulators and difference frequency generation [PRR-22].

Operation in the 2 µm range

The original dual-comb setup I studied was operating around 1.55 µm, which is not highly suitable for spectroscopic applications. The idea was then to extend the spectral region analysis of the spectrometer to around 2 µm. For this, I developed an electro-optic dual-comb setup directly at 2 µm [OL-19], and also studied four wave mixing in a highly nonlinear fiber [CPHYS-18].

Figure: Optical spectrum recorded at the output of a highly nonlinear fiber where we can observe the frequency conversion by four wave mixing from 1.55 µm to around 2 µm [CPHYS-18].

References

[OFC-24] Alexandre Parriaux, Kamal Hammani, and Guy Millot, “Spectroscopy with electro-optic dual frequency combs,” Chap. 9 from the book “Optical Frequency Combs - Trends in Sources and Applications”, edited by Auro Michele Perego and Andrew Ellis, (2024).
DOI: 10.1201/9781003427605

[PRR-22] Alexandre Parriaux, Kamal Hammani, Christophe Thomazo, Olivier Musset, and Guy Millot, “Isotope ratio dual-comb spectrometer,” Physical Review Research 4, 023098 (2022).
DOI: 10.1103/PhysRevResearch.4.023098

[AOP-20] Alexandre Parriaux, Kamal Hammani, and Guy Millot, “Electro-optic frequency combs,” Advances in optics and photonics 12, 223-287 (2020).
DOI: 10.1364/AOP.382052

[OL-19] Alexandre Parriaux, Kamal Hammani, and Guy Millot, “Electro-optic dual-comb spectrometer in the thulium amplification band for gas sensing applications,” Optics Letters 44.17, 4335-4338 (2019).
DOI: 10.1364/OL.44.004335

[CPHYS-18] Alexandre Parriaux, Kamal Hammani, and Guy Millot, “Two-micron all-fibered dual-comb spectrometer based on electro-optic modulators and wavelength conversion,” Communications Physics 1, 17 (2018).
DOI: 10.1038/s42005-018-0017-4