Introduction to Optical Fiber, Optical Fiber

INTRODUCTION TO OPTICAL FIBER

An optical fiber is a dielectric wave guide that operates at optical frequencies. This fiber-wave-guide is normally cylindrical form.

Physically, an optical fiber is a very thin and flexible medium having a cylindrical shape, consisting of three section, core, cladding and protective jackets as follows:

(i) The Core
(ii) The Cladding
(iii) The Protective Jacket

Thus an optical fiber can be considered as a transparent coaxial cable having core of higher refractive index and cladding, the external cable of lower refractive index. In low and medium loss fiber, the core material is generally glass which is surrounded by plastic cladding.

Principle of Optical Fiber, Optical Fiber

PRINCIPLE OF OPTICAL FIBER

An Optical Fiber is a thin flexible, transparent dielectric wave guide strand meant for communication light signal through it. It is based on the principle of total internal reflection (TIR). Light ones trapped within the fiber without being lost. An Optical Fiber consists of a core at the center with refractive index〖 n〗_1. This core is surrounded by cladding whose refractive index 〖 n〗_2 is slightly lower than 〖 n〗_1. outside the cladding a protective jacket called sheath is attached. The basic function of this sheath is to provide mechanical strength to the fiber and prevent it from abrasions due to surrounding.