In fiber optics, what does the term "core" refer to?

The term "core" in fiber optics specifically refers to the light-carrying part of the fiber. The core is the central region through which light travels, and it is surrounded by the cladding, which has a lower refractive index and causes light to be reflected back into the core, enabling the propagation of light signals efficiently over long distances.

Understanding the role of the core is crucial for grasping how fiber optic communication works, as variations in core diameter can affect the number of modes of light that can propagate through the fiber, thereby impacting the performance characteristics such as bandwidth and distance capabilities.