PhD position in opto-microwave (M/F)

Job Description

Thesis Subject

The generation of broadband optical frequency combs has enabled numerous applications, including the calibration of astronomical spectrographs, the detection of exoplanets through high-resolution spectroscopy, and ultra-precise optical metrology [1]. The major impact of this technology on measurement science was recognized by the 2005 Nobel Prize in Physics awarded to Theodor W. Hänsch.
Fiber Fabry–Pérot resonators, consisting of a few centimeters of optical fiber bounded by two highly reflective dielectric mirrors (99.9% reflectivity), can achieve finesse values as high as 3×10
4. Their compact size and straightforward integration into all-fiber architectures make them an attractive platform, while the wide variety of available optical fibers provides considerable technological flexibility.
The objective of this PhD project is to build upon previous work [2] by investigating the wide range of nonlinear regimes accessible in these resonators, with the aim of generating broadband optical frequency combs through the formation of ultrashort pulses with durations on the order of one hundred femtoseconds. Ultimately, this research will contribute to the development of ultra-stable coherent optical sources as well as low-phase-noise microwave and millimeter-wave signal generators.
The project will be carried out within the MOST research group at LAAS-CNRS and will be primarily experimental, complemented by theoretical modeling and numerical simulations performed in collaboration with partner laboratories. The PhD will be conducted within a strong collaborative framework involving PhLAM (Lille), ICB (Dijon), Institut Fresnel (Marseille), and IRMAR (Rennes) as part of the ANR COMBY project (2025–2029).

Keywords: Kerr frequency combs, Fabry–Pérot cavity, optical solitons, microwave synthesis, phase noise.
Required skills: nonlinear optics, signal processing, feedback control systems (PID), numerical simulations (MATLAB).

References

[1] T. Fortier and E. Baumann, "20 years of developments in optical frequency comb technology and applications," Communications Physics, vol. 2, p. 153, 2019.

[2] G. Bourcier, S. Balac, J. Lumeau, A. Moreau, T. Bunel, A. Mussot, M. Conforti, V. Crozatier, O. Llopis, and A. Fernandez, "Laser self-injection locking to a fiber Fabry–Pérot resonator for frequency comb generation," IEEE Journal of Lightwave Technology, 2025, DOI: (to be completed).

Your Work Environment

Research conducted at LAAS-CNRS in Toulouse aims to achieve a fundamental understanding of complex systems while taking into account their potential applications. Conversely, many industrial and societal challenges—for example in transportation, space, healthcare, and communication networks—raise fundamental scientific questions that drive the laboratory's research projects.

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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