Introduction to Bragg Fiber

The recent advancements in integrating different materials with distinct optical, electronic, and thermomechanical properties into a single multilayer fiber (known as Bragg Fibers), drawn from a preform, are leading to the development of a new generation of multi-material multilayered fibers. These Bragg Fibers (BFs) possess exceptional functionalities that can be achieved at the length scales and costs associated with optical fibers. Various distinctive devices have been created so far in the shape of fiber utilizing this approach, including transversely emitting fiber lasers, fibers with the ability to sense light, heat, or sound on their outer surfaces simultaneously, fibers with crystalline semiconductor cores, narrow band inline filters, optical d-mux, temperature sensors, strain sensors, and various bio-chemo sensors. The use of these BFs in the next fabrics will result in textiles with advanced functionality. Incorporating many materials in BFs optics has effectively resolved persistent challenges encountered in conventional optical fiber applications. For instance, hollow-core all-solid-cladding fibers have successfully utilized photonic bandgap guiding to overcome concerns related to conventional optical fibers. Similarly, soft-glass mid-infrared fibers have been strengthened mechanically to enhance their durability. We provide in this chapter, an overview of the latest advancements in this emerging subject, which is seeing tremendous growth. Additionally, we emphasize the areas where further expansion is expected. Moreover, the findings derived from this research indicate novel approaches in which the fiber drawing process might be utilized as a manufacturing methodology. Specifically, we discuss current endeavors, natural inspirations, and historical developments to date of multi-material multilayered Bragg fibers in subsequent sections of the chapter.