An optical fiber is a flexible filament of very clear glass capable of carrying information in the form of light. Optical fibers are hair-thin structures created by forming pre-forms, which are glass rods drawn into fine threads of glass protected by a plastic coating. Figure 11-16 depicts the fiber optic core and coating.
Fiber manufacturers use various vapor deposition processes to make the pre-forms. The fibers drawn from these pre-forms are then typically packaged into cable configurations, which are then placed into an operating environment for decades of reliable performance.