Optical fiber cables, how do they work? | ICT #3

Have you ever thought about how you get emails or any other information, from any corner of the world, within a blink of an eye? This has been made possible by a network of cables, which are laid under the ground and below the ocean. The cables, which carry most of the world’s data, are optical fiber cables. They are also used in medical equipment. Let’s learn how optical fiber cables work, and how they have revolutionized the world around us.

[BranchEducation]

Really great information. Optical fibers really are quite fascinating! Another really cool thing is that you can use up to 80 or so different colors of light (or wavelengths of light) in a single fiber, it's called wavelength-division multiplexing and it increases the bandwidth by 80x!

[cognitivedissident]

The people who invented all of these are the true geniuses.

[keshavarora]

What I learned from this video..
Optical fibers
1. thickness comparable to that of a human hair.
2. transfers data at a very high speed because of the use of the light as the carrier.(or we can say that they carry information in form of light), (due to this we are able to do this exchange of information in an only blink of an eye.)

Principle : It is based on the principle of Total Internal Reflection of light

TIR:
a) when light travels from denser to rarer medium it bends away from the normal.
b.) angle of incidence should be larger than the critical angle.

Critical angle: angle at which the refractive angle becomes 90 degrees.
structure of the optical fiber:

core: innermost part of the optical fiber. and light travels through this part of the fiber.

cladding : middle part of the fiber having refractive index less than the core in order for the total internal reflection to happen

sheath: the outside protective layer of the fiber.
material used: mostly these optical fibers are made of glass(silica) or plastic.

In case of using glass as the material, both the core and the cladding are made of the glass and some dopants are added in order to make cladding of lower refractive index.

attenuation: this is the loss of the power of signal. Could include various causes like scattering, absorption etc.

So there are amplifiers installed at certain distances to again power up the signal and cover up for the losses.

Now whenever you send some information through your phone, your information is converted into a code of 0's and 1's, based on already set parameters. This converted signal is send to the tower in form of a wave, where 1 is send a high frequency while the 0 is as a low frequency.
now at the tower if the electromagnetic wave is of high frequency then a light impulse is generated, otherwise for a lower frequency no impulse is generated.

As we also know that amplifiers are installed at certain distances to cover for the losses during the transmission (this loss we termed as attenuation), now the question arises how we will be covering up for this loss when these optical fibers are laid down under the sea and oceans .
Here the cable is much larger in diameter and only very small part of it is actual optical fiber that is carrying the signal. The outer part is the protective coverings.
so here a copper shell runs in the cable itself to supply power to the amplifiers.
optical fiber vs copper cables
1. as the speed of light is always more than the speed of electrons, the optical fiber cables transfer the information at much higher speed.
2. also the flow of electrons inside the copper wire produces a magnetic field and thus is at the risk of magnetic interference due to some outer field.

first the optical fiber were used in endoscopy, here the doctors can see what is happening inside the body of the patients.




(the reason to do this is to not just become a consumer of content, but to actually understand and write it in your own words so as to activate neural pathways in the brain).

[kenkioqqo]

My biggest question about fibre optic cables had always been "How does the information travel through the fibres?" Now I understand...when your device sends out your message (eg test message), nearby transmission towers convert it into binary numbers (1s and 0s), then every 1 travels as a light pulse and every 0 travels as the opposite of a light pulse (i.e no light pulse) through the fibres. On the other end, the receiver converts all light pulses into 1s and all no light pulses into 0s, then the ones and zeros are converted into machine code, which is then converted into human language that you can read. Amazing to learn this today.

[Singh.RichyRich]

I used to be a fibre splicer and it takes a lot of practice and patience to strip a piece of glass thinner than human hair. It’s fascinating to watch them join when the arc is fired by the machine. It’s just amazing.

[dennischanayiwa]

I'm studying software Engineering in Zimbabwe with a local Varsity. I have a course on networking and um a week away from exams and this video just saved me. Good informative video. It answered a lot of my questions

[ctrlzme.]

This was actually such a great video for people with no background in physics like me. Thank you!

[jayrockya]

When the instructor said the light can only be sent 100km before needing to be re-amplified. I was wondering how do they get it across a whole ocean?
Man i was on the edge my seat till i got the answer. What great illustration of how this works. Thank

[bryanbridges]

Two minutes and fifty-seven seconds in, and I was blown away. I've heard that engineers tend to think man can do anything, and no wonder! Look at what we do now!

[whiteboardmedicaljournalwm]

Thank you for the video. I am actually a medical doctor but really enjoy learning more about engineering! All the best!

[Fedelisk]

Great video! There are some heavy inaccuracies though. The two big ones are:
-The speed at which information travels in the copper cable is not necessarily less than an optical fiber!!! Its speed is given by c/n, where n is the root of relative permittivity of the material, it has nothing to do with electrons!! The reason why optical fibers transmit more information is due to the fact that they have a much greater bandwidth.
-Copper cables are usually coated and do not leak EM fields, especially at higher frequencies.

[tigrayrimey]

Amazing concept behind Optical fiber cables! Light, signal, Refraction, TIR, Modulation, bits, EMW are the core elements in OFC. Thanks for the wonderful explanation!

[sodam]

I didn't major in engineering and don't know much about it. But I always have the curiosity. Thank you for this video!

[reekymirror]

1:49, just casually injecting some glass with dope

[new_donker]

All your data is just instructions which can be translated in a light turning on and off. It's just amazing.

[TONYSTARK-otmm]

Better than teaching in a classroom. Thanks for posting this knowleageable ideas.

[kondaparthisandeep]

I cleared my uncleared topic for many years from school age to graduation thank u so much.

[cszhluo]

Thank you so much. I really appreciate your effort of creating tutorial videos like this to spread your wisdom to the world. Please make more videos about networking, it's really helping me a lot. God bless ❤❤❤

[grinishkin]

Just a tiny note. The speed of electrons in copper cables is slow indeed, but it doesn't really matter for data transfer. What is important is the speed of electromagnetic pulse which is close to to the speed of light as in the case of optical cables. Still, optical cables are much more efficient than copper ones.

[nedjmanana]

I have a "optical fiber" course this semester ! Your video helped me to get an idea about it thank you !