BSAIBES Maroun: Towards a better understanding of light scattering and mode coupling mechanisms in slightly multimode optical fibers.
Thesis Summary: The continuous increase in the volume of information exchanged in the World’s telecom networks, combined with the saturation of the transmission capacity of conventional optical fibers, leads to the emergence of new fibers. While the latter are logically tested primarily in data transport experiments, it turns out that more upstream issues have so far been left aside, such as questions about the loss mechanisms (Rayleigh scattering and diffusion linked to the core/cladding interface, known as SALS) or their nonlinear properties, which are important to quantify both for the benefit they can bring (optical amplification of the signals by Raman effect) and for the undesirable effects that they can generate (signal backscattering via the Brillouin effect). This is particularly true in the case of few mode fibers (FMF) which allow several transverse distributions of the light in their core (modes) which thus "experience" their own interaction with the waveguide. It is the goal of this thesis to understand and quantify (i) the effects that are causing the degradation of the quality of data transmission in a FMF, through the study of the Rayleigh scattering and SALS of the different modes, as well as the threshold of stimulated Brillouin effect, (ii) the stimulated Raman effect that can be used to improve the quality of transmission by distributed optical amplification along the fiber. In practice, the student recruited will implement experiments to quantify, for different modes of different FMF, scattering parameters and thresholds. The results obtained, in particular in the Rayleigh / SALS case, will be integrated into a theoretical model aiming at a better description of mode coupling. This work will be carried out in close partnership with Prysmian group, whose fiber production center is based in Douvrin.
BSAIBES Maroun - maroun.bsaibesuniv-lille fr
Thesis supervisor: BIGOT Laurent
Co-supervisors: QUIQUEMPOIS Yves