PhD Thesis Offer in Optomicrowaves and Nonlinear Optics (M/F)

Job Description

Thesis Subject

The generation of broadband optical frequency combs has paved the way for numerous applications, including the calibration of astronomical spectrographs, the detection of exoplanets through high-resolution spectroscopy, and ultra-precise metrology [1]. The major impact of this work on measurement science was notably recognized by the Nobel Prize in Physics awarded to Theodor W. Hänsch in 2005.

Fiber Fabry–Pérot resonators, consisting of a few centimeters of optical fiber bounded by two highly reflective dielectric mirrors (99.9%), can achieve finesse values of up to (3\times10^4). Compact and readily integrable into fully fiber-based architectures, they offer significant technological flexibility owing to the wide variety of optical fibers available.

This PhD thesis aims to build upon previous work [2] by exploring the diversity of nonlinear regimes accessible with these resonators, with the objective of generating broadband frequency combs through the production of ultrashort pulses on the order of a hundred femtoseconds. In the longer term, these developments will enable the realization of highly coherent and ultra-stable optical sources, as well as low-phase-noise microwave and millimeter-wave signals.

The research carried out within this PhD project may lead to patentable solutions.

The project will be conducted within the MOST team at LAAS-CNRS. The work will be primarily experimental, complemented by modeling and numerical simulations carried out in collaboration with other researchers. The PhD thesis will be part of a strong collaborative research effort involving PhLAM (Lille), ICB (Dijon), Institut Fresnel (Marseille), and IRMAR (Rennes), within the framework of the ANR COMBY project (2025–2029).

The candidate should ideally have a background in fiber-based nonlinear optics, with complementary knowledge in optomicrowaves. Beyond these technical skills, a strong interest in research is essential. This includes an enthusiasm for scientific investigation, the ability to work effectively within a team and contribute to collaborative research, as well as the ability to communicate results clearly and regularly through well-structured and rigorous reports.

Finally, perseverance in the face of difficulties and negative or unexpected results is a particularly important quality for the candidate we are seeking. The ability to critically question experimental results, learn from unsuccessful approaches, and pursue investigations with rigor and determination is an essential part of the research process.

Keywords: Kerr frequency combs, Fabry–Pérot resonator, soliton, microwave synthesis, phase noise.

Required skills: nonlinear optics, signal processing, 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, 153 (2019).

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

Your Work Environment

Research conducted at LAAS-CNRS in Toulouse aims to achieve a fundamental understanding of complex systems while also considering their potential applications. Conversely, many industrial and societal challenges, for example in the fields of 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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