Optical Fiber - Definition, Uses, Types, Advantages and How it Works

Definition

Optical fiber is the technology that deals with the transmission of the data with the help of light waves that travel along a fiber made of conducting material. Metals are usually preferred as the transmitting material due to rapid transmission of the data and less maintenance cost.

Optical fibers are unaffected by electromagnetic interference. The phenomenon used to transfer the light from the optical fiber is total internal reflection. These optical fibers in such a way that they must propagate light and messages along a long-distance depending upon the requirement of power and the distance up to which the data has to be transmitted. Multi-mode optical fibers transmit data for shorter distances, while single-mode fiber is used to transmit the data for a longer distance. The cladding, which is the outer protection of these optical fibers, must be made of good material to serve their purpose for a longer duration without much wear and tear.

Materials used to manufacture optical fibers

The following materials are used to manufacture optical fibers and cladding of the optical fiber-
1. Silica
2. Fluoride glass
3. Phosphate glass
4. Chalcogenide glass

While calculating the stress that the fiber may experience in the future under various bend and rough situations, the thickness of the coating must be taken into consideration. The stress experienced by the coated material is given by-

111

Here, E is the fiber’s Young’s modulus, df is the diameter of the cladding, dm is the diameter of the mandrel, and dc is the diameter of the coating.

This will help to determine the thickness of the optical fiber coating. The bandwidth of the optical fiber is 900 THz.

Uses of optical fibers

Optical fibers are used for the following circumstances-

1. For a more extended communication distance
2. To make efficient sensors
3. In power transmission to transfer power up to a more considerable distance
4. Used in light guides
5. Microscopes
6. Endoscope, a device used to view objects via a small hole
7. Optical fiber lamps
8. Structural health monitoring devices
9. Spectroscopy

Types of optical fibers

Optical fibers types depend upon the material used, refractive index, and the mode of light propagation.

Based on the refractive index, optical fibers are classified as-
1. Step index fibers – They consist of an enormous core, which is surrounded by cladding and has a single uniform index of refraction.
2. Graded index fibers – In these fibers, the refractive index decreases as the radial distance increases.

Based on materials, optical fibers are classified as-
1. Plastic optic fibers – These fibers are made from polymethylmethacrylate. This material is used to make the core of the optical fiber for the propagation of light.
2. Glass fibers – The core in these fibers is made of fine glass.

Based on the mode of propagation of light, optical fibers are classified as-
1. Single-mode fibers – These are used to transmit data over a long distance.
2. Multimode fibers – These are used to transmit data over a shorter distance.

Based on the mode of propagation of light and the refractive index, the core is designed in the following combinations as well-
1. Step index – multimode fibers
2. Step index – single-mode fibers
3. Graded index – single-mode fibers
4. Graded index – multimode fibers

Advantages of optical fibers

Less signal degradation
Flexible and lightweight
The data security is excellent
It is cost-effective
It is unaffected by interference
Economical and cost-effective
Less power consumption
Thin and non-flammable

How does optical fiber work?

The principle involved in the working of an optical fiber is total internal reflection. Light rays are used to transmit a large amount of data. There is only one problem in this transmission – light rays travel in a straight line. As a result, the bending of optical fibers should be significantly less to transfer a large amount of data without any hindrance. This makes the application of optical fibers a tedious process. These light rays also bounce back again and again from the walls of the optical fibers so that the data is transmitted up to a more considerable distance without fail.

An optical fiber system consists of the following-
1. Transmitter – Used to produce light signals and encode them.
2. Optical fiber – A medium to transfer data via light impulse.
3. Optical receiver – It receives the light signals transmitted via transmitter and decodes them.
4. Optical regenerator – It is a significant component that is used to transmit data over longer distances.

Frequently asked questions on optical fibers

Ques: Which is the best material to transfer data in optical fibers?
Ans: Silica is one of the finest materials that can be used to transmit data. It is abundantly available on earth and can also be used for fabrication purposes.

Ques: What are the factors responsible for generating attenuation of the power of an optical fiber?
Ans: The factors responsible for generating attenuation of an optical fiber's power are – scattering, absorption, and waveguide effect.