Chromium-based coatings for lasers – CRUMBLE

The objective of this project is to develop a new coating with saturable absorption and gain medium properties dedicated to telecom applications. This coating is based on YAG: Cr4 + nanocrystals embedded in a sol-gel matrix. The chromium-IV doped YAG is indeed known for its saturable absorption properties around 1060 nm, and also exhibits an amplifying behavior around 1550 nm with a very wide gain bandwidth. However, this material is little used because it is difficult to integrate into existing technologies. During the project, we will aim at producing a coating compatible with both the glass integrated optics platform and the microlasers technology of Teem Photonics, our industrial partner. This study will thus have the potential to increase the portfolio of applications of Teem Photonics in the short term through its integration as a saturable absorber and in the longer term as a gain medium. Two different optical devices will be produced: i) a pulsed microlaser in which our material will be the saturable absorber, reducing the pulse duration of the devices produced by Teem Photonics; and ii) an integrated optics amplifier on glass, in which our coating will be the gain medium. The latter is the first step towards manufacturing an integrated mode-locked laser.

This project will be carried out by a consortium of three laboratories and a private company. The three laboratories present a strong synergy allowing the complete development of the proposed coating. On the one hand, the ICCF laboratory in Clermont Ferrand specializes in the development of nanocrystals for optics, in particular based on the YAG matrix. On the other hand, the LaHC laboratory in Saint-Etienne masters the manufacture and characterization of sol-gel coatings and their doping with nanocrystals. Finally, the IMEP-LaHC laboratory specializes in integrated optics on glass and the hybridization of thin coatings on such waveguides. This consortium is completed by the company Teem-Photonics, a specialist in pulsed lasers. This industrial partner will be involved from the start of the project on the qualification of the reliability of the material, so as to ensure that the coating developed during the project is compatible with an industrial application.