BFS Hot Bragg

German company

Reliable high temperature sensors are a necessity for various industrial processes. To date, however, the development of these sensors for high-temperature applications, their design and fabrication is a major scientific challenge. Sapphire-based optical sensors represent a promising solution for temperatures beyond 1000 °C, but their optical properties are still far from ideal measurement purposes.

The aim of the Hot Bragg research project is to develop a new two-step ultrashort pulse laser-based process for the fabrication of high-temperature optical sensors. In a first step, the diameter of the sapphire fibre is to be reduced to a few micrometres by a laser turning process. In combination with individually calculated cross-sectional geometries, so-called windmill structures, optical waveguides with optimal optical properties are produced.

In a second step, the same laser system is used to realise a direct writing process to generate periodic refractive index modulations in sapphire fibres. In this way, the complete high-temperature sensor can be manufactured on a single system without the need for time-consuming repositioning. In addition to the optical and mechanical characterisation, the project also includes a detailed and highly accurate investigation of the sensor performance in an accredited calibration laboratory of the industrial cooperation partner.

• Ultra-short pulse laser lathe
• Simple writing process for generating structures with Bragg grating sensor technology
• Optical simulation of waveguide properties