Fiber optic internet sends data not as electrical signals, but as pulses of light. These pulses travel through incredibly thin strands of glass or plastic called optical fibers. It’s a bit like sending Morse code with a flashlight, but happening millions of times per second and over vast distances.

Each fiber optic cable is a bundle of these tiny strands. This technology allows for a huge amount of information to be sent very quickly and reliably. Imagine the difference between a garden hose and a fire hose—fiber optics offers a much wider pipe for data to flow through.

A fiber optic cable isn't just a simple glass thread. It has three main parts designed to keep the light signal contained and protected.

1. Core: The very center of the fiber, where the light travels.
2. Cladding: A layer of material that surrounds the core. It has a different optical density, which is key to trapping the light.
3. Coating: A protective outer layer that shields the core and cladding from damage and moisture.

The magic that keeps light inside the core is a principle called total internal reflection. Light travels down the core, bouncing off the boundary with the cladding like a ball ricocheting down a hallway. This happens because the cladding is designed to have a lower refractive index than the core. When light hits the boundary at a shallow enough angle, it reflects perfectly instead of escaping.