Maha Bouhadida's thesis defence

Thesis defense of Maha Bouhadida, PhD student in the Nonlinear Photonics group, on March 24 at 2 pm on the topic: "Study of non-linear optical effects of orders 2 and 3 in optical nanofibers".

Summary of my work:

This PhD thesis deals with the study of 2nd and 3rd order nonlinear optical effects in silica optical nanofibres which are optical fibres stretched to wavelength diameters.

The first application studied is the realisation of wavelength converters in the visible range in the sub-nanosecond regime, a domain not well covered by current pulse sources. The principle of these converters is based on stimulated Raman scattering in the evanescent field of a silica optical nanofibre bathed in a liquid. By defining and optimising their operating range, we have achieved external conversion efficiencies from the pump wave at 532 nm to the first order Stokes of ethanol at 630 nm close to 60%. The performance of our converters is highly repeatable and paves the way for a new family of very compact, efficient, reliable and fully fibrous wavelength converters.

The second targeted application concerns the study of a source of correlated photon pairs emitting around 1.5 μm for quantum telecommunications. Our source is based on the parametric fluorescence mechanism at the surface of a silica optical nanofibre. In the studied modal phase tuning, the pump wave is emitted on the TM01 mode at 775 nm and the correlated photon pairs are generated around 1.5 μm on the HE11 fundamental mode, with the advantage of being able to recouple with minimal losses in a fibre grating. Our studies focused on the choice of the standard fibre to optimise the efficiency of the mechanism, the design of the nanofibre and its tapers, and the implementation of preliminary experiments for the excitation of higher order modes.