Due to their properties of transparency in the infrared region, their weak intrinsic losses and their ability to be deposited in thin film form, chalcogenide glasses are good candidates for the design of infrared micro-components. Moreover, they are also characterized by weak phonon energies, making them materials of choice in the realization of active components, functioning at the wavelengths of telecommunications. It is in this context that the activity based on the “valorization of chalcogenide glasses for integrated optics” was born some ten years ago in the team.
We fabricated singlemode waveguides operating from 6 to 20 µm. This success was possible thanks to: the presence of an engineer to support the experimental work at ICG, the purchase of the co-evaporation equipment and a ion beam etching set-up, the existence of a strong consortium including at the same time chemists from the University of Rennes 1, specialists in the design in the optical components from the IMEP in Grenoble, group of opticians from the LEMTA in Nancy.
With our experience in the realization of infrared waveguides, one of our current objectives is the production of micro-sensors for monitoring the environment or biology. Through a study of the Te-Ge-Se ternary system, we isolated a range of compositions particularly attractive in terms of thermal stability, refractive index and transmission area. We then started manufacturing various waveguide structures from these compositions: straight waveguides, curved waveguides, Y junctions and Mach-Zehnder interferometers. All these structures were first optimized for operating at the wavelength of Telecommunications (1.55 m) and are currently under consideration for operating at 4.26 microns, wavelength corresponding to carbon dioxide absorption. To characterize the structures, we equipped the team with an optical characterization bench operating at this specific wavelength of 4.26 microns. The bench is currently hosted at the IES, and optical characterizations are carried out with the help of Mr. Raphael KRIBICH, lecturer in Teho team.
In parallel, we try to consider other applications for our devices based on thin-film chalcogenide: supercontinuum generation, production of optical transistors, etc.