"so there's a peltier cooler underneath the platform holding the lasers and first optical stage so that the optic can electrically heat or cool the lasers to keep them at the right temperature! "
I get that Peltier coolers are simple, solid state devices, but still. Between that and the prisms and lenses, the amount of complexity here is mind blowing.
I'd expect that sentence to come from a hard sci-fi novel about weapons on an orbital platform or something. Instead, it's a pinky-sized bit of tech working to send cat videos to our phones. Amazing!
I'm surprised they use flip chip tech in something this expensive. Flip chips tend to be sensitive to light and this is after all a laser module. Raspberry pi had lots of issues with photosensitivity in its flip chip wifi controller. Use flash nearby and it would reset.
If it were me I'd just spend the 10c for the plastic..
Also really surprised the laser colors are only 4.5nm apart!
The size is amazing by the way.. I worked with fiber tech in the late 90s and a 16-colour DWDM multiplexer was the size of a full rack!
> Flip chips tend to be sensitive to light and this is after all a laser module
If a laser shines through to the chip then your SFP is dead already. SFP module has a metal case, SFP socket has a metal casing and usually surrounded in more metal around, be it a switch or a server.
100G-LR4 is a technology that's on its way out, and this illustrates why. Muxing four 25G lanes is complex and costly and these days also unnecessary at 100G.
100G is going single lambda.
This is still the way to build 200G/400G/800G optics, though.
It's 8×100G yeah, but they also use two fiber pairs so four lanes go on each.
The QSFP-DD modules are also bigger (they stick out further from the slot) and have more power available, so that probably helps somewhat with engineering.
It's fascinating to think you can combine and split signals on the fly with prisms. It should be completely obvious but I've never thought about it, my mind is far too set into digital habits. By comparison electronics feel so slow.
Those are not prism. Prism implies it used as dispersion component, which is not the case. The thing does the real work there is the dichroic thin film coating on those prism shaped glass.
Am I reading right that there's a direct interaction between magnetism and optical polarization? I know that light polarization is a pretty wacky topic to start with, but having magnets in the mix makes it seem unlikely amounts of wacky to me!
The sibling comment has a link to the Wikipedia page, yet for a quick video explanation and demonstration Applied Science's video on the Faraday Effect was fantastic. It demonstrates it, explains some use cases, and also goes into how the material the light is passing through affects the strength of the magnetic induced rotation.
That sounds very wrong.
Not a physicist, but light does not interact with magnets, or you need to get into the superconducting strength levels before it does.
Magnet there is probably used as an isolator. The laser can only go out,but not come back.( yes, there will be laser coming back from reflection, which also interrupt the operation of the source laser.
A facinating teardown! I wonder how long it will be before we manage to get 100G over reasonable copper length. https://en.wikipedia.org/wiki/100_Gigabit_Ethernet says we can have 100GBASE-CR4 for 7m but no Cat8 yet.
Copper's loss tangent is high. There's no getting around that. PAM4-based 50GBASE-CR DACs have similar length.
Twinax has more bandwidth than STP. We're at the physical medium's limits. Sure, you can pump the voltage but that quickly hits diminishing returns. Best to use copper for sub 1 meter and fiber otherwise.
I'd guess never. Twinax maybe, but "Cat8" would probably be more expensive than fiber above few metres already. Fiber is cheap, it's fancy electronics, lasers and photodiodes that make the thing expensive, but once you're there per metre price is cheap.
one of the challenges there is that you can't do PoE over fiber, so for common house use with things like security cameras and 802.11ac/ax access points, you still want copper.
Yes, any level of bend-insensitive fiber has a better bend radius than cat6a. a3/b3 is much better.
Cat6a min bend radius is about an inch.
g.657a3/b3=~0.2 inch
g.657a2/b2=~0.39 inch
g.675a1/b1=~0.59 inch
as for connectors, not anymore.
They have simple ones that are just mechanical crimp.
IE you cleave it, crimp it, and that's done.
0.15-0.25db loss, which is fine for a home run.
also, LC connectors/etc are small enough that you can just fish them (they are less than half the size of a cat connector), or disassemble them and re-assemble.
I have a fusion splicer, but i just fish completed cables with the connector covered.
Also, these days you can get a reasonable fusion splicer on amazon for ~750 bucks that is 0.025db average loss.
There are less and less reasons to run cat these days.
QSFPTEK just emailed me this morning offering me multimode 100G-SR4 optics (100M, so same as ethernet) for 35 bucks a piece.
They are regularly only 50 bucks a piece now anyway.
100G is obviously crazy for anyone's home need, but the point is the speed at which things like it are becoming cheaper is really high right now.
I guess "just" terminating them would be fine if you just installed it once but at least looking at tutorials it does look like a PITA compared to CAT connectors
A lot of tutorials are old. Mechanical splices have improved very quickly in the past 5 years.
Talking with my friend who is an home automation installer, he says they now just use mechanical crimp splices and they don't take them longer than, say, prepping and terminating a coax cable. He says it's definitely shorter now than the average time they spend trying to untwist, straighten, and line up wires in a cat connector.
They used to use connectors requiring polishes that took 30 minutes
mechanical splices should absolutely be avoided if at all possible, we live in the era of $900 made in china core alignment fusion splicers that are not terrible.
Because the interface this module plugs into is not specific to optic data transmission. Also, remember how LEDs and lasers want constant current. A regulator circuit would be required anyway.
The poster puts over 1100 characters in one of the posts, while the default Mastodon server limits to 500 characters. It may be more about images - I think there's a default maximum of 4 images per post, so overall it kind of makes sense to tie each post's text with the matching image(s).
I don't understand how it is "rate limiting" when I was first viewer from IP, and most likely from entire IP class (it's 6AM here in office and there is nobody here, and I'm the admin of the infrastructure so I'm pretty sure literally nobody else accessed it)
Also displaying "rate limited" in some retarded popup that instantly disappears while page reads "404 not found" is some top tier level of UX idiocy, I didn't even notice because I usually open both HN post and page so it just... displayed in the background when I wasn't looking and only refresh of the page showed it...
So I waited a minute, refreshed, then the site told me to wait 5 more minutes...
Tried on mobile (via 4g to get different IP) and it is just "not found", not even a popup
I'm imagining this idiotic attempt at throttling is direct effect of Mastodon being just so fucking slow and someone trying to patch it via more bad design
Can the downvoter please explain the vote of non-confidence? It does make it hard to read what is written when the server denies access after all, something which I think to be quite relevant in this context.
Mastodon is a great example of pathetic web design. More than a few times has it completely failed to work for me at all just as in your case.
Every single instance I've used has presented me with the same warning: "To use the Mastodon web application, please enable JavaScript" as I have JS disabled by default. Please, PLEASE tell my why I can't see anything on the page without Javascript. What amazing cutting-edge Twitter-busting follower-thrusting technologies could Mastodon possibly be using that it needs me to turn on JS to see absolutely anything?
Mastodon uses the open protocol ActivityPub, which means you can access posts like these from many other clients than the servers web interface. If you dislike JavaScript, may I suggest 'Brutaldon' [0]? There is also the cli/tui client 'toot' [1], if you prefer to live in the terminal.
Using a client to access posts in the fediverse network do require that you have an account somewhere in the fediverse, though.
I smell some anti-herd "feature" where user instance never saw gets mandatory timeout to avoid site being fucked every time something on it gets popular.
At first it just said "site not found" and then it reloaded normal for me on firefox mobile (on android).
Once it reloaded, I found it nicer to read, than a Twitter thread, but if I want to publish something, I would not find that tolerable. Not loading is a clear signal it might work later, but showing a "content does not exist" tells me as a user to go somewhere else.
> Once it reloaded, I found it nicer to read, than a Twitter thread, but if I want to publish something, I would not find that tolerable.
This is perfect example of "it should've been just a blog post". Kinda shame Mastodon repeats same Twitter failures, instead of just giving an option for long format content. I mean, it is nicer than Twitter formatting-wise but that's a low bar
I get that Peltier coolers are simple, solid state devices, but still. Between that and the prisms and lenses, the amount of complexity here is mind blowing.