How Does LIGHT Carry Data? - Fiber Optics Explained

How do fiber-optic communications work?

[betterinbooks]

This is actually how fiber optics carry light rather than how light carry data.

[bccbuue]

I used to work on fiber optic equipment (wrote the software, but still had to know a good amount about the hardware). The way light carries data can be much more complicated than just flipping the light on and off. The transponder I worked on used 16QAM modulation sending the data in a combination of the amplitude and phase of the light, allowing for 4 bit symbols (any one reading from the fiber provides 4 bits). We transmitted at 200 gigabits per second (per slot within the ROADM network).

[uss_]

I tried absorbing data directly through Light mode and now my Retinas are scorched.
#NoFilter

[morgan]

But Linus, I thought you only stuck RGB lighting up there.

[scellyyt]

"minecraft redstone doesn't relate to reality at all" well now I have an objection

[leggo]

As an EE, I’m super impressed with how well this was explained!

[AnAverageJho]

Optical fibres that carry useful information over long distances are usually single-mode C-Band Telecom fibers. The "C-Band" refers to an optical window where Rayleigh scattering (the effect that makes the sky blue) and glass absorption meet to create minimal absorption of telecom wavelength (around 1550nm).

[element]

0:40 could you have possibly picked a creepier picture of a hallway?

[nightowl]

As a high school physics teacher, I never knew about the repeaters and amplifiers. Instead, I always told my students about the wonders of eternally efficient fiber cables. Turns out air-resistance can't be neglected after all eh?

[edtheoldtechguy]

I am a IT consultants that became a network and fiber optic engineer and have been in the trade for many moons. Linus you should have mentioned the difference between single mode and multimode as their limitations are different. This is a very entertaining way to explain how light travels through a fiber but not necessarily how data travels or how its converted to light, we missed packets, frames, and labels, you also forgot to mention the vacuum in the fiber strands which allows for light to travel further. Nothing on attenuation or operation at 1310nm or 1550nm.
Next you glanced over wavelengths possibly due to time but Wave division multiplexing that grew into DWDM and its advances to go from 1Gbps and 10Gbps to 40, 100, 400Gbps are the reason global bandwidth has grown. Then 0 layer switching, it is what allows for light to be switched on demand without physical intervention. You could spend half an hour on that alone, Dont even start on ROADM's LOL. Also the chemical reaction discussed in helping light travel further only works with certain types of fiber strands, the rest need a physical regeneration point closer, converting light to electrical then back to light again, about every 80 or so kilometers. The physics of light energy at the output level disburses or degrades at this length, even in a vacuum or in a perfect reflective environment. So all major telecoms depending on the type of fiber whether Corning Leaf 0 dispersion have to plan their repeaters carefully. You never mentioned ITU standards like G.651 or 652. Again possibly due to time. It's actually a hodgepodge of network cable out there all working differently at different lengths of regeneration points. The advances in Switches and Routers has allowed for full use of these hodgepodge networks. By the way I have been a loyal fan for years now, and this subject should not be a tech quickie but I will say this was an admirable go at it, and a very good explanation. I know veterans in the field that could not explain it to a customer as simple and as graceful as you did. As I recently became a YouTube creater I know how hard this is. Props to you and your staff Linus!

[brewergamer]

Ahh this took me back to when I was a telecommunications technician. I genuinely enjoyed learning about how the internet was created. I do miss it alot.

[philipcooper]

If you ever built a tree fort, .... secret message using a flash light... Kids today: U wot m8?!

[keevanorosco]

Job Recruiter: what are your qualifications?

me: i watch Techquickie

Job Recruiter: you're hired!

[Charlesb]

Thanks for shedding some light on this technology.😄

[uniqhnd]

It's amazing how accurately you've portrayed this information in such a short and simple manner

[reprevise]

missed opportunity tho at 0:11, could've said "works in the same LIGHT" hahahahaha I'm so funny

[MuitoDaora]

"Look at light at molecular level". Oh no!

[bbasmdc]

This is a great basic explanation. There are a few inaccuracies, however that could be corrected without making this explanation longer or more complex.


Modern optical fibre does not make use of total internal reflection – we could never really go much further than a couple of kilometres if that was still the case. It actually uses a refractive index gradient (as opposed to a hard boundary) to guide the light back into the fiber. Check out the difference between step index fibre and graded index fiber.


Repeaters vs amplifiers. Hmmm…to be honest these two terms are interchangeable, but they both just mean “amplifiers”, and more specifically “optical amplifiers” (like EDFAs, SOAs or Raman amps). You may have meant to compare amplifiers to regenerators – which digitally recreate the signal, as opposed to an analogue amplifier. Regenerating signals is expensive compared to just amplifying them, so the goal in modern long distance communication is to send the signal at the highest possible data rate as far as you can before you have to resort to regeneration. But you may still amplify that signal about every 50-80 km.


Just to note that optical fiber was used in endoscopy way before it was used in communications, at least in terms of commercial products. Endoscopy dates back to the mid 1800s using hollow tubes, but fiber endoscopy was invented in 1957. The use of fiber for communications was triggered in 1970 when two technologies reached a sufficient state of usefulness that commercial products could be created. These two technologies were low loss optical fibre and semiconductor lasers.

[EastyyBlogspot]

I had a endoscope and a colonoscopy and i was afraid they would meet in the middle

[seruputhirudan]

Why do I learn more in YouTube than in my school.. ....?