Kazumara
Here, I found the original, unfortnuately on Instagram: https://www.instagram.com/alwaysyzy/p/C5KdNvmrJiT
Edit: I forgot, we’re on Lemmy! I can just post the picture here:
What is special about today?
Fuck I just set up a Windows Server 2022, because Space Engineers Dedicated Server is officially supported under Windows only.
First of all some corrections:
By constructing a device called an optical processor, however, researchers could access the never-before-used E- and S-bands.
It’s called an amplifier not processor, the Aston University page has it correct. And at least the S-band has seen plenty of use in ordinary CWDM systems, just not amplified. We have at least 20 operational S-band links at 1470 and 1490 nm in our backbone right now. The E-band maybe less so, because the optical absorption peak of water in conventional fiber sits somewhere in the middle of it. You could use it with low water peak fiber, but for most people it hasn’t been attractive trying to rent spans of only the correct type of fiber.
the E-band, which sits adjacent to the C-band in the electromagnetic spectrum
No, it does not, the S-band is between them. It goes O-band, E-band, S-band, C-band, L-band, for “original” and “extended” on the left side, and “conventional”, flanked by “short” and “long” on the right side.
Now to the actual meat: This is a cool material science achievement. However in my professional opinion this is not going to matter much for conventional terrestrial data networks. We already have the option of adding more spectrum to current C-band deployments in our networks, by using filters and additional L-band amplifiers. But I am not aware of any network around ours (AS559) that actually did so. Because fundamentally the question is this:
Which is cheaper:
- renting a second pair of fiber in an existing cable, and deploying the usual C-band equipment on the second pair,
- keeping just one pair, and deploying filters and the more expensive, rarer L-band equipment, or
- keeping just one pair, and using the available C-band spectrum more efficiently with incremental upgrades to new optics?
Currently, for us, there is enough spectrum still open in the C-band. And our hardware supplier is only just starting to introduce some L-band equipment. I’m currently leaning towards renting another pair being cheaper if we ever get there, but that really depends on where the big buying volume of the market will move.
Now let’s say people do end up extending to the L-band. Even then I’m not so sure that extending into the E- and S- bands as the next further step is going to be even equally attractive, for the simple reason that attenuation is much lower at the C-band and L-band wavelengths.
Maybe for subsea cables the economics shake out differently, but the way I understand their primary engineering constraint is getting enough power for amplifiers to the middle of the ocean, so maybe more amps, and higher attenuation, is not their favourite thing to develop towards either. This is hearsay though, I am not very familiar with their world.
The zero dispersion wavelength of G.652.D fiber is between 1302 nm and 1322 nm, in the O-band.
Dispersion pretty much linearly increases as you move away from its zero dispersion wavelength.
Typical current DWDM systems operate in the range of 1528.38 nm to 1563.86 nm, in the C-band.
Group dispersion in the E-band and S-band is lower than at current DWDM wavelengths, because these bands sit between the O-band and the C-band.
over 90 channels of 400G each
You mean with 50 GHz channels in the C-band? That would put you at something like 42 Gbaud/s with DP-QAM64 modulation, it probably works but your reach is going to be pretty shitty because your OSNR requirements will be high, so you can’t amplify often. I would think that 58 channels at 75 GHz or even 44 channels at 100 GHz are the more likely deployment scenarios.
On the other hand we aren’t struggling for spectrum yet, so I haven’t really had to make that call yet.
Disaggregated compute might be able to leverage this in the data center.
I don’t think people would fuck with amplifiers in a DC environment. Just using more fiber would be so much cheaper and easier to maintain. At least I haven’t heard of any current Datacenters even using conventional DWDM in the C-band.
At best Google was using Bidir Optics, which I suppose is a minimal form of wavelength division multiplexing.
He uninstalled systemd, now his computer is not doing systemd things anymore by his retelling. Seems like it worked fine. Yet he asks for a solution of a problem. Maybe he needs to state the problem.