0000000000432432
AUTHOR
Kilian Baudin
Wave dynamics and turbulence in multimode optical systems
The subject of this thesis essentially focuses on the experimental and theoretical study of optical turbulence in different types of nonlinear media. The first part of the manuscript is devoted to the study of thermalization and condensation of optical waves during their propagation in graded-index multimode fibers. The analysis based on the wave turbulence theory reveals that the disorder inherent to light propagation in an optical fiber induces a significant acceleration of the process of optical thermalization, which can clarify the mechanism of certain regimes of spatial beam cleaning recently reported in the literature. We show experimentally that the optical field relaxes during its p…
Weak Langmuir turbulence in disordered multimode optical fibers
We consider the propagation of temporally incoherent waves in multimode optical fibers (MMFs) in the framework of the multimode nonlinear Schr\"odinger (NLS) equation accounting for the impact of the natural structural disorder that affects light propagation in standard MMFs (random mode coupling and polarization fluctuations). By averaging the dynamics over the fast disordered fluctuations, we derive a Manakov equation from the multimode NLS equation, which reveals that the Raman effect introduces a previously unrecognized nonlinear coupling among the modes. Applying the wave turbulence theory on the Manakov equation, we derive a very simple scalar kinetic equation describing the evolution…
Intense Stimulated Raman Scattering in CO2-filled Hollow Core Fiber
International audience; Frequency combs are of constant significant interest for their use in diverse areas of physics ranging from metrology to biomedical and environmental spectroscopy. One of interesting techniques to obtain multi-octave comb-like optical spectra is based on generation of higher-order stimulated Raman scattering (SRS) in a hollow-core photonic crystal fibers (HC-PCFs) filled with hydrogen gas [1]. The ability of these types of fibers to strongly confine together gases and laser pump, while keeping their interaction length over several meters, has allowed to reduce, by six-order of magnitude, the laser power in comparison to previous equivalent techniques using a gas cell…
Fiber-based measurement of temporal intensity and phase profiles through self-phase modulation
International audience