What is Optical Fiber and How does it work

Have you ever thought about getting emails or any other information in the blink of an eye from any corner of the world? This is made possible by a network of cables laid underground and under the sea. The cables that carry most of the data in the world are optical fiber cables.They are also used in medical equipment. Let us learn the working of optical cables and how it changes the technology in this article.

Image of optical cable

Optical Fiber Cables:


Optical fiber cable is made up of thousands of fiber strands.And a single fiber strand is as thin as a human hair.Optical fibers carry information in the form of light.Let's first learn some fundamental behaviors of light to understand the workings of optical fibers.The speed of light changes when it passes through a medium.And this change in speed is expressed by the refractive index.This variation and the speed of the light leads to another interesting phenomenon.Refraction,to understand what it is,let us carry out an interesting experiment.In this experiment,light passes through a prism.You can see that at the interface the light gets bent instead of going straight.This phenomenon is know as refraction.
                                                      
characteristics of optical fiber cable

Refraction:

Refraction occurs when light passes from a medium with a one refractive index to one with another refractive index.The light bends towards the interface when it goes from a medium of high to one of low refractive indices.Refraction is the reason why a pencil looks bent in a glass of water.This simple refraction technique effectively used in optical fibers. Now,let's make this experiment a hypothetical one.Using some dopants we are able to increase the refractive index of the glass in real time.As we increase the refractive index,the light will bend more and more towards the surface.After a time you can see that,the light will pass through the surface of the glass.

If we increase the refractive index further,the light will suddenly come back to the first medium as a pure reflection.This is called total internal reflection.The total internal reflection is possible if we increase the incident angle rather than increasing the refractive index.In this case at a certain angle called the critical angle,the light will come back to the first medium.This phenomenon of total internal reflection is used in optical fiber cables to transmit the light.

Cylindrical glass with a high refractive index.If the laser strikes the interface at an angle greater than the critical angle,total internal reflection will happen and the light will reach the other end.This means that light can be confined in the optical fiber over a long distance.No matter what complex shape the fiber forms.Remember,total internal reflection happens between the high refractive index of glass and the low refractive index air.


Protective Coating For Optical Fiber Cables:

However,optical fibers need a protective coating.A protective coating is not possible with this configuration.The introduction of protective material will replace the position of the air and cease the total internal reflection phenomenon.An easy way to overcome this issue is to introduce a low refractive index glass above the core glass known as cladding.This way total internal reflection will happen and we'll able to use a protective layer.Both the core and the cladding use silica as their base material.The difference in the refractive index can be achieved by adding different types of dopants. 

Protective coating of optical cable

The optical fiber we have just constructed won't be able to carry signals for more than 100 kilometers. This is due to various loses that happen in the cable.This lose of signal strength is generally called attenuation.Absorption and scattering are the main reasons for signal attenuation.This is why you see amplifiers and cables after a certain distance.They boost the signal strength and allow signals to be transmitted over a long distance.The power required for the amplifier is drawn form nearby sources.

How Does Fiber Optics Work:

Now, to the main topic, how does optical fiber transmit information like phone calls or internet signals? Any information can be specified in zeros and ones form. Suppose you want to call a person through your mobile. The code is converted to a series of zeros and one equivalent binary code. After the change your mobile phone will transmit these zeros in the form of electromagnetic waves.One transmits high frequency and zero low frequency waves.Your local cell tower picks up these electromagnetic waves.

At the tower,if the electromagnetic wave is of high frequency,a light pulse is generated.Otherwise,no pulse is generated.Now these light pulses can easily be transmitted through optical fiber cables.The light pulses which carry the information have to travel through a complicated network of cables to reach their destination.For this purpose the entire world is covered with optical fiber cables.These cables are laid under the ground and below the ocean.It is mainly the mobile service providers that maintain these underground cables.AT & T,Orange and Verizon are some of the few global players who own and maintain the submarine cable network.A detailed cross section view of an undersea cable is shown here.

You can see that only a small part of the cable is used to hold the optical fiber. The rest of the cable is a mechanical structure for protection and strength. Now the question is, where does the power come from multiplying under these deep oceans?For this a thin copper shell is used inside the cable, which carries electricity with the cable so that the amplifiers can run. This whole discussion is that if optical fiber cables simply do not reach a part of the world, that part will be isolated from the Internet or mobile communications.



Copper Cable Vs Fiber Optic Cable:

Compared to traditional copper cable and optical fiber cable, optical fiber cable is superior in almost all respects. Fiber optical cables offer larger bandwidth and transmit data at higher speeds than copper cables.This is because the speed of light is always higher than the speed of electrons. The flow of electrons in a copper cable creates a magnetic field even outside the cable, which causes electromagnetic interference. On the other hand, light travel through optical cable is always limited to fiber.

Comparison on optical fiber and copper cable


Thus not having the opportunity to interact with an external signal. An interesting feature about optical fiber cables is that any light signal entering from the side has the least chance of traveling on the cable. Optical cable provides greater data protection.You will be surprised to learn that optical fiber was first used in endoscopy before it was used in the telecommunications industry. In telecommunications, digital pulses are replaced by optical fiber cable. However, in endoscopic cables, visual signals in analog form are transmitted to the other end.




Connect With Us:
My official page in Facebook. Do follow by click onto this link and keep supporting.My official page in Instagram. Do follow by click onto this link and keep supporting.My official page in Quora. Do follow by click onto this link and keep supporting.My official page in Pinterest. Do follow by click onto this link and keep supporting.My official page in Twitter. Do follow by click onto this link and keep supporting.





Post a Comment

2 Comments