What is the purpose of cladding in a fiber optic cable?

The purpose of cladding in a fiber optic cable is fundamentally to reflect light back into the core. The cladding is made from a different type of glass or material that has a lower refractive index compared to the core. This difference in refractive indices facilitates the phenomenon of total internal reflection, which is essential for light to effectively travel along the core without escaping. This reflective property ensures that the light signals can travel long distances with minimal loss of strength, making fiber optic cables highly efficient for data transmission.

The assertion that cladding serves to provide physical protection, reduce cable weight, or enhance flexibility, while they may have some relevance in terms of overall cable design, do not address the primary optical function of cladding in capturing and sustaining the light within the core. Each of these alternative functions plays a lesser role compared to the critical function of light reflection and maintaining signal fidelity, which is the core purpose of cladding.