9. Microstructured fibers

9.1 Appearance of microstructured fibers

In the mid-1990s, a new type of optical fiber appeared in research laboratories: microstructured fibers, where "micro" here means "of the order of magnitude of the wavelength of light". They are also known as "hole" fibers, "photonic crystal" fibers or "photonic bandgap" fibers, depending on which type they belong to. The main players in academic research were the University of Southampton, long known for its role in the development of optical fibers, and the University of Bath in Great Britain, as well as the Technical University of Denmark (TUD). These organizations have led to the creation of start-ups dedicated to industrializing products based on research findings.

The periodic structure of their refractive index...