Rishi556 :unverified:
Clement CavadoreWhy you should NEVER look directly an optic fiber panel: you dont know the power of the signal 🔥
Source: https://www.reddit.com/r/FiberOptics/comments/167jjlh/is_the_signal_too_strong/
PlasmaGryphon@acontios if it's 1500+ nm it might "only" burn the front of your eye while <1300 nm stuff will refocus on your retina and can be worse than the tape shows. To be clear, I'm not pro-burning-front-of-your-eye either.
I've seen LSOs discount hazards of fibers because the light diverges so quickly from them it is technically safe after ~10 cm and, "no one will stick it in their eye."
A really bad combo is when it's around 800 nm, looks really dim because your eyes can't see it very well, but it's actually bright AF. Then people actually jam it up to their eye to check if it is working.
Poslovitch@acontios Now I know what my retina turned into. TIL. 🤣
Joke aside, I didn't expect the ray to be this powerful (as in, able to uncomfortably heat organic material that are about a centimeter close to the outlet). At least the one that gets sent in "domestic" optic fiber.
Good to know! :)
tobozo@acontios next level: tattoo machine from PoF appliance
PowerLight Power over Fiber
Maddler 
@acontios ah, how many times I've seen people "checking" that... 😶
Miha Markič
Elias Probst@acontios why isn't there some power negotiation protocol for fiber optics? Even if it's just a "continually increasing the output to level X until there's an ACK from the other side"?
jaseg@eliasp @acontios I suspect because (within reason) there is no such thing as "too much signal" on the receiving end, and because beefy transmitters are expensive, so you'd usually only use them where you need to.
Technically, any sort of negotiation would require a well-defined return channel, and unlike RJ-45 ethernet, in fiber interfaces transmitters and receivers don't always come in pairs. For instance, they can be separate SFP modules, or you can have multiple TXs light up the same fiber.
Expired Token
Dr. h.c.* Grober Unfug@eliasp @acontios depending on your transceiver this is already dangerous to your eye, remember one pulse is enough for permanent damage.
And there is some Power throtteling for diagnostics and Power savings and such stuff.
And to be honest, while I work with more dangerous lasers and can control everything on them personally i would never rely on anything like that for eye safety IMO it's inherently dangerous work practice.
Leah Neukirchen
vampirdaddy@acontios
I worked with a laser with 18W electrical input.
Pulsed, so 5 GW/cm^2 unfocused - which obliterated "safe with industrial laser cutting" in a nanosecond. Even unfocused.
Laser diodes might only be laboed as "1.5W" - but on a singlemode fibre that’s 1.5W on 50nm diameter.
For comparison: on a dime (50mm diameter) that laser intensity would need a 1.5MW laser…
LR@acontios wow that's an alien toot. what the hell am i even looking at %) what is that pen. what is a fiber optics panel
feel free to mansplain, i implore you
Nick Taylor@lritter The pen is either an optical transmission module or the end of an optical fibre connected to one. In normal operation, electrical signals get converted to pulses of near infra-red light (usually 1310 nm or 1550 nm) and that white bit at the right would be clamped against a matching bit on an optical fibre, which will carry the signal for (wild guess based on the power here) a few hundred miles. At the far end the much-attenuated light will get converted back to electrical signals.
@lritter The light coming out of that white bit has to be quite intense to be detectable after that much distance, so it's intense enough to make black electrical tape smoke.
You do not want this to happen to your eyes.
@lritter A fibre-optics panel is a bunch of these mounted next to each other, into which you plug fibres. Some of these fibres will be going across the room, and have low-power transmitters on them. Some will be going a long way. If those long-distance fibres have been unplugged, the connector they should be plugged into can be emitting literally eye-searing invisible radiation.
@tienelle ahhh! now i get it. so this signal would likely be transmittable over a very long distance since its power is so high, hence even under attenuation by inverse squared distance (through a reflective fiber cable though), it would be unlikely to degrade below ambient noise levels
Ayron 
@lritter that's the point. The light output of an fibre optic transmitter is lower than that of a flash-light bulb. Looking into the filament of a 100W incandescent light bulb hurts in the eyes. Looking into a 58W fluorescent tube is no problem, although the fluorescent tube outputs about 4 times more light.
tocisz@acontios wow, that's an interface to produce smoke signals 😁
Simon Zerafa
Anthropy@acontios luckily for us all the longhaul fibers are in a single place in the datacenter, but man those things are spicy, if the fiber wasn't cleaned appropriately before engaging it can literally melt the entire connector and port, and it's mostly infrared so you won't see it.
Use IR visualizer cards! Better to burn a piece of replaceable paper/plastic than your retina.
If you work with fiber a lot, consider keeping one on your belt/pocket like your work badge, so you won't be tempted to look
@acontios
That reminds me of a customer, who's fiber link went down, where he told me that he looked into the cable and did not see any light. The colleagues at the fiber team quite panicked about that. In that case he was lucky as the link was actually down.
That reminds me of a customer, who's fiber link went down, where he told me that he looked into the cable and did not see any light. The colleagues at the fiber team quite panicked about that. In that case he was lucky as the link was actually down.
Andy Nonimose@acontios Ah, yes, the forbidden DIY lasik
Wulfy—Speaker to the machines
bigiain@acontios “Do not look in laser beam with remaining eye”
val = int(1)
Erik Ableson@acontios @unixwitch Yup. reminds me of a client site where my loaned out storage server was having issues until I discovered that *all* of their 10GbE SFP+ modules were rated for 10km connections even though they were for local connections in the same server room. Sigh.
Explained to networking team that « up to 10km » didn’t mean it was optimal for 10m connections while indeed being under 10km. I think my SFP+ I was using is cooked. 🤦♂️
w4tsn ~> 
@acontios Star Trek Phasers is just optic data cable science gone wrong
Aris Adamantiadis 
💲Paid@acontios Don't look with the remaining eye. Free retina surgery
MadMike77
F4GRX Sébastien (@[email protected])
Attached: 1 image Wow. Did you know this? There exist *power over fiber* components that can provide 3v 180mA from 1.5W of 800nm infrared light coming through a standard multimode optical fiber. These are very expensive, but also very cool! https://www.farnell.com/datasheets/2785190.pdf
x0r@acontios That signal-to-noise ratio must be over 9000 dBm.
T4$
Benedikt@acontios didn't know, haven't had fiber In my Hand yet. Thanks for sharing
Arkadiusz Wieczorek@acontios a consumer cable will not have such a signal
Tattie@acontios I like to imagine it's streaming videos of cute kittens playing
Dani 
@acontios I feel like these things need some kind of safety cap on the end. Even as someone who considers herself not a dumbass, I'm always worried I'll eventually have an accident. (Doesn't help that I have had a laser to the eye before.)
Space Hobo@acontios A decade ago, at my last employer, our legal counsel made us a laminated card to hang on the network rack that had the laser hazard symbol and said "DO NOT LOOK INTO LASER WITH REMAINING EYE."
Aroop Roelofs@acontios Guess if I really am in need of a lighter, I can just use my fiber for a bit. :')