An optical fiber is a flexible and transparent material made out of glass and extruded in the form of fibers. Optical fibers are used as wave guides or light pipes for transmitting light between the two ends of the fiber. Optical fiber cables have a thickness that is slightly greater than that of human hair.
Glass and plastic are the commonly used materials for making optical fibers. Optical fibers are coated on the outer surface with some polymers for mechanical protection. Glass fibers are usually made of silica. The three main parts of the fiber are core, cladding and the outer protective layer. The core has a high refractive index and the cladding has a low refractive index.
Working Principle of Optical Fiber
Fiber optics is based on the theory of total internal reflection of light. When light travels from an optically dense medium and hits the boundary at a steep angle, it is completely reflected. By using this principle, the light is confined within the core (which is optically denser), light bounces back and forth between the core and the cladding.
Types of Optical Fiber
There are two main types of fiber, multimode and single mode. An optical fiber with a large core diameter is called a multimode fiber. Single mode optical fibers have a core diameter in the order of 8-10 µm.
Applications of Optical Fiber
Some of the typical applications of optical fiber are listed below:
- Fiber optic communication
- Fiber optic sensors
- Light guides in medical field
- Gain medium in lasers
Sources and Further Reading