General information
Organisation
The French Alternative Energies and Atomic Energy Commission (CEA) is a key player in research, development and innovation in four main areas :
• defence and security,
• nuclear energy (fission and fusion),
• technological research for industry,
• fundamental research in the physical sciences and life sciences.
Drawing on its widely acknowledged expertise, and thanks to its 16000 technicians, engineers, researchers and staff, the CEA actively participates in collaborative projects with a large number of academic and industrial partners.
The CEA is established in ten centers spread throughout France
Reference
SL-DRT-24-0478
Direction
DRT
Thesis topic details
Category
Technological challenges
Thesis topics
Inscription of Optical Waveguide in Silica or Saphirre Optical Fbers and Characterization at High Temperature
Contract
Thèse
Job description
Fiber Bragg Gratings are structures, photo-inscribed with femtosecond laser, inside the fiber core and can be used as band pass optical filters (centered around the Bragg wavelength). Bragg wavelengths are easily multiplexed and they give to us the necessary information. Silica-based fiber Bragg gratings are point sensors and can measure temperature up to 1200°C. For higher temperature, sapphire based optical fiber are used, since they can withstand temperature up to 2000°C. However, the sapphire optical fiber is coreless, which leads to an extreme multimodal behavior. Consequently, the measure is less precise and the signal-to-noise ratio is low, compare to a classical silica-based grating. Moreover, each modification of the fiber surface, change the grating spectra.
The thesis objective is the creation of an optical waveguide inside the sapphire fiber, which will leads to less propagation modes inside the fiber, in order to obtain new perspectives for the monitoring in high temperature environments (airplane engines, nuclear reactors, …), which is one of the missions of the DRT/LIST-DIN. To obtain this result, the photo-inscription of a cladding is necessary: the cladding will be ring shape and the internal diameter – i.e. the core – will be few tenths of micrometers. Other techniques are also investigated, such as ion implantation, to create an amorphous sapphire cladding. Then these new structures will be characterized up to 2000°C and under high dynamic pressure (> 10 GPa).
University / doctoral school
Sciences Chimiques: Molécules, Matériaux, Instrumentation et Biosystèmes (2MIB)
Paris-Saclay
Thesis topic location
Site
Saclay
Requester
Position start date
01/09/2024
Person to be contacted by the applicant
BLANCHET Thomas thomas.blanchet@cea.fr
CEA
DRT/DIN//LSPM
CEA Saclay,
Laboratoire Systèmes et Photoniques pour le Monitoring
Bat 516, pièce 38D,
91 190 Gif sur Yvette, France
0169085256
Tutor / Responsible thesis director
LANCRY Matthieu matthieu.lancry@u-psud.fr
Université Paris Saclay
Institut de Chimie Moléculaire et des Matériaux d'Orsay
Université Paris-Saclay
Rue du doyen Georges Poitou
91405 Orsay Cedex
FRANCE
01 69 15 62 18
En savoir plus
https://www.linkedin.com/in/phd-thomas-blanchet/