Structure of Optical Fiber
The optical fiber is made up of two concentric cylindrical strands of silica surrounded by a plastic coating. The center most silica strand is the cone of the fiber with a refractive index1 of approximately 1.48. The core of the fiber physically transports most of the optical power. The core is surrounded by another strand of silica called the cladding. The cladding has a slightly lower refractive index, 1.46 and provides the interface that confines the optical signal to the core. The outermost layer of the optical fiber is the buffer coating. This thin plastic covering protects the glass from mechanical and environmental damage. A pictorial representation of the components that makeup an optical fiber is shown in figure 2.
