0000000000523523
AUTHOR
Adrien Fusaro
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…
Spatiotemporal Complexity in Step-Index Multimode Fibers
We study supercontinuum generation in step-index fibers with a varying number of modes. We observe new spatiotemporal effects, including evidence of multimode spectral incoherent solitons, and a universal transition to spatiotemporal complexity.
Self-organization of incoherent optical waves : Condensation, thermalization and repolarization
The subject of this thesis concerns the study of phenomena of self-organization of incoherentoptical waves. This work is essentially theoretical and numerical and relies on different formalisms of waveturbulence theory, the Hamiltonian singularities, and different experiments.The first part of the thesis deals with the irreversible processes of thermalization and condensation ofincoherent waves. The phenomenon of condensation is characterized by the formation of a large scale co-herent structure (condensate) that remains immersed in a sea of small scale fluctuations (uncondensedparticules). In spite of the large propagation lengths required to reach the condensed equilibrium state, wehave i…