Graphene-coated optical fibers for sensor applications

Optical fiber coatings are essential for the performance and reliability of the optical fiber in application. For most applications, standard coatings such as acrylates and polyimides are used, providing good protection against mechanical and chemical ambients. For high temperature applications, up to 300°C, polyimide coatings are industrial standard. 

In this project, funded by the Swedish innovation program SIO Graphene, we developed methods to coat long lengths of optical fiber with graphene/polyimide nanocomposite (NC) coatings. Several properties of the as-coated fibers proved interesting for sensor applications, as validated in the project.

• The NC coated fibers are (slightly) more robust against high temperature ageing in air, with the fiber strength retained longer than standard polyimide coated fibers. 
• The NC coating is electrically conductive (kOhms/cm) and can be used for heating the fiber. 
• The NC coated fibers show significantly less moisture-induced strain than standard polyimide coated fibers. This is particularly important for FBG-sensor applications. 

The project has shown, for the first time, the production of long length optical fibers with polyimide coating enhanced by the integration of graphene and graphene oxide particles. Further exploration of this, and other nanocomposite coatings, is on-going at RISE. Reach out if you're interested in collaborating on this topic! 

Publications from the project:

• Hey Tow, K., et al., "Graphene-material based nanocomposite-coated optical fibres: a multi-functional optical fibre for improved distributed sensing performance in harsh environment", Journal of Lightwave Technology, 2024 (link).
• Hey Tow, K., et al., "Nanocomposite-coated optical fibres for improved distributed sensing performance in harsh environment", 28th International Conference on Optical Fiber Sensors. 2023 (link). 

This work was supported (2021-05094) by Sweden’s Strategic Innovation Programme for Graphene, SIO Grafen, funded by the national innovation agency Vinnova, Swedish Energy Agency, and Formas.