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Tumblr post by trippedintoa-volcano:
Imagine that everywhere in the mechanical engineering world suddenly got infatuated with lasers.
Lasers have a lot of uses! Measuring things, heating things, cutting things, entertaining cats, particle physics. Lasers are pretty cool. Very versatile, very useful, potential to be very powerful.
Someone shows up one day and says "I have developed a never before seen technology! I call it a Death Star."
And it's a 3.4mW laser. Well no, we haven't seen this exact size of laser much since that's not really standard, but that's a bit of a misnomer, and I wouldn't call it new -
"HOLY SHIT GUYS! This Death Star is so entertaining! My cat loves it and it has such a nice color!" The Death Star becomes a viral novelty, and is mildly entertaining, as laser pointers often are.
Somehow, seemingly overnight, this leads to mania. "Lets stick lasers in EVERYTHING! The public loves them!"
More companies make 3.4mW lasers to jump on the bandwagon. Everyone that makes anything vaguely mechanical starts sticking lasers into their designs.
Everyone is calling them Death Stars. Any time there is a "Death Star innovation", it is just that they made a bigger laser.
Ford's next truck comes out and it has "Death Star integrated headlights", where they have just stuck giant lasers in place of their previously functional headlights.
An electric toothbrush is now "Powered by Death Stars" and shoots a laser at the tooth its cleaning. You think that maybe this could have actual applications as a sanitizing device if you're being generous, but when you actually look at the product, its laser has no purpose but to point at the tooth and drain the battery.
Mechanical products across the board get noticeably worse as everyone starts stuffing lasers in places where lasers have no right to be.
The lamp business gets in on it. "Here's a Death Star powered lamp!" These guys haven't even tried to stick a laser in their damn lamps. They've just started calling their light bulbs Death Stars and hoped you bought it before you could tell the difference. You at least appreciate that they haven't ruined their lamp about it.
Death Stars are lauded as the solution to all the world's problems. If it's not working, you should stick a laser in it! That'll fix it, everyone says. Once in a blue moon, it's even true! Weather prediction is really good now. But most things are garbage. Like "Death Star powered washing machines". What the fuck does that even mean?
Meanwhile, since all functioning mechanisms are being replaced with lasers, problems start showing up. All mirrors now cost $1000+ dollars, because the whole supply is being used up to make more lasers. The earth heats up, because everyone's blasting lasers at everything. People keep going blind, on account of all the lasers.
You, in fact, study optical mechanics. You know what a laser is, and how it works, and that it was invented many years before any of this nonsense actually started. People keep asking you about Death Stars, since surely you must know so much about them.
You explain that this is not really what lasers are for, except you have to call them Death Stars now, and that they're causing a lot of harm, so you don't like them much.
"Oh, but they're still such new tech!" they reply. "They'll figure out how to make Death Stars that don't burn your eyes out soon, and then it won't be an issue anymore!"
Somewhere, deep and buried, you remember lasers being used in particle accelerators, or in telescopes, or in laser cutters, or funny cat videos. They are, in fact, still interesting. Still cool.
But by this point they have replaced roads with "Death Star Powered Pathways", which are just laser pointers propped up on tooth picks pointing vaguely through the forests.
And you think you are going mad.
And they are still just FUCKING LASERS.
This post is about Al.
Tags: #scribbles by trip
cynar's answer is very good already so I'll just add one thing: You're not even that wrong.
In so called Short Range (SR) transceivers, 850 nm LEDs were in fact used too. At least for the 1, 10 and 100Mbit/s generation.
That was before my time in the industry. Here's what I know anyway:
For SR transmission you use fiber optic cables with a 50 (or 62.5 in the older OM1 standard) micrometer diameter of the core. This is called multimode fiber, because the transmission uses multiple modes of the light. The wider core allows more light to be captured even from a more spread out light source like an LED.
Contrast that with single mode fibers that have only 9 micrometer of core diameter, which allows only a single mode of light to pass, but keeps the signal cleaner in turn. You also use longer wavelengths which experience less attenuation from the fiber material itself (1310 nm and 1550 nm are two particularly important ones).
For the short range however you don't need all that, you could get away with LEDs and multimode, so it is a cheap way of connecting devices within a data-center or between floors of a building for a few hundred meters.
However I believe starting from 1Gbit/s up to at least 25Gbit/s the multimode SR world has moved to laser sources, particularly VCSELs. Those are cheap lasers made with semiconductor techniques, emitting vertically out of a chip. They are still not as precise as the proper DFB lasers used for single mode transmission, but they can achieve higher output than LEDs, and more of the light is captured into the fiber, which is still multimode.
The for the 100Gbit/s generation they started using four lanes of 25 Gbit/s each that's called SR4, and for that they made connectors that had 8 fiber cores, all of them multimode, 4 four sending 4 four receiving. And for 400G there is SR8 with 50Gbit/s per lane. So the VCSELs are still used.
I think maybe LEDs are still used for the optical audio link TOSLINK, but I'm not an audio guy, so I'm not sure.