What Is Optical Fiber?


What is an Optical Fiber?

Optical fiber is the technology associated with data transmission using light pulses travelling along with a long fiber which is usually made of plastic or glass. Metal wires are preferred for transmission in optical fiber communication as signals travel with fewer damages. Optical fibers are also unaffected by electromagnetic interference. The fiber optical cable uses the application of total internal reflection of light. The fibers are designed such that they facilitate the propagation of light along the optical fiber depending on the requirement of power and distance of transmission. A single mode fiber is used for long-distance transmission while a multimode fiber is used for shorter distances. The outer cladding of this fibers needs better protection than metal wires.

How Does an Optical Fibre Work?

The optical fiber works on the principle of total internal reflection. Light rays can be used to transmit a huge amount of data but there is a problem here – the light rays travel in straight lines. So unless we have a straight long wire without any bends at all, harnessing this advantage will be very tedious. Instead, the optical cables are designed such that they bend all the light rays’ inwards (using TIR). Light rays travel continuously, bouncing off the optical fiber walls and transmitting end to end data. Although light signals do degrade over progressing distances, depending on the purity of the material used, the loss is much less compared to using metal cables. A Fibre Optic Relay System consists of the following components:

  • The Transmitter – It produces the light signals and encodes them to fit to transmit.
  • The Optical Fibre – The medium for transmitting the light pulse (signal).
  • The Optical Receiver – It receives the transmitted light pulse (signal) and decodes them to be fit to use.
  • The Optical Regenerator – Necessary for long distance data transmission.

Types of Optical Fibers

Optical fibers are classified into different types based on the refractive index, materials used and mode of propagation of light.

The classification based on the refractive index is as follows:

  • Step Index Fibers
  • Graded Index Fibers

The classification based on the materials used is as follows:

  • Plastic made Fibers
  • Glass made Fibers

The classification based on the mode of propagation of light is as follows:

  • Single Mode Fibers
  • Multimode Fibers

The mode of propagation and refractive index of core is used to form four combination types optic fibers as follows:

  • Step index-single mode fibres
  • Graded index-Single mode fibres
  • Step index-Multimode fibres
  • Graded index-Multimode fibres

Advantages of Optical Fibre Communication

  • Economical and cost effective
  • Thin and non-flammable
  • Less power consumption
  • Less signal degradation
  • Flexible and lightweight

Learn more about optics, fiber optics, its application and about multimode fibers from our expert tutors at BYJU’S.


Practise This Question

The refractive index of a prism is 2.This prism can have a maximum refracting angle of