Researchers achieve optical data transmission speed of 44.2 terabits per second • Hacker News Board

Re: Researchers achieve optical data transmission speed of 44.2 terabits per second

#41

Post by dasudasu » Sat, May 23, 2020, 4:24 PM UTC

It is not particularly hard to do a "hero" experiment like this. Shannon limits to fiber transmission have pretty much been reached experimentally a long time ago. Muxing several wavelengths together is also of course the backbone of fiber optics transmission since its very origin. The current buzz in the field is to use micro-combs like they did as opposed to an array of lasers to provide the multiple wavelengths - but it still comes with its particular set of challenges to make it practical. The micro-comb provides the other wavelengths from a single source through a nonlinear process.

My understanding from just looking quickly at the paper is that they don't modulate all the wavelengths independently, meaning that they duplicate the info they send several times to reach that high terabit rate. The laser source is only one part of a transceiver, and once you have 400+ independent modulators/receivers, the laser source becomes a much smaller concern when it comes to make it practical. A conventional laser source can be made very compact too (in a semiconductor platform) and integrated with the rest of the transceiver on the same chip. This is still where the industry is putting its efforts. These micro-combs come with some disadvantages too, relating to stability, low SNR, and uneven power among the wavelengths (that then need to be equalized).

Re: Researchers achieve optical data transmission speed of 44.2 terabits per second

#42

Post by govg » Sat, May 23, 2020, 4:25 PM UTC

TheSpiceIsLife wrote: post #25

keenmaster wrote: post #21

Is anyone knowledgable on the implications of the underlying tech once it gets commercialized? Obviously things like game streaming would be improved.

Aren’t gamers primarily concerned with latency rather than speed ?

Both latency and bandwidth affect gaming. Latency is important to ensure that there isn't too much lag between you moving a controller stick and your character moving, and not as important for slower games which can handle this well. Bandwidth is important because it determines the resolution and quality you can stream at, so higher bandwidths would enable full HD or 4K gaming.

Re: Researchers achieve optical data transmission speed of 44.2 terabits per second

#43

Post by TheSpiceIsLife » Sat, May 23, 2020, 4:30 PM UTC

TheAdamAndChe wrote: post #30

TheSpiceIsLife wrote: post #25

Earlier quoted context omitted.

Aren’t gamers primarily concerned with latency rather than speed ?

They said game streaming, which makes me think s/he's talking about things like Twitch and Mixer, livestreaming platforms that do depend on throughput for high quality video.

Sorry, yes, I see that now.

Re: Researchers achieve optical data transmission speed of 44.2 terabits per second

#44

Post by rayiner » Sat, May 23, 2020, 4:38 PM UTC

bobajeff wrote: post #5

I like like the bottle neck in the future will be Harddrive/SSD file read/write speeds. Honestly, I'd love to have my hands on a terabyte drive with 1TBps speeds.

It’s not even the future. 40 gig Ethernet is already faster than most SSDs. And you can get a card on eBay for $200.

Re: Researchers achieve optical data transmission speed of 44.2 terabits per second

#45

Post by IdiocyInAction » Sat, May 23, 2020, 4:49 PM UTC

bobajeff wrote: post #5

I like like the bottle neck in the future will be Harddrive/SSD file read/write speeds. Honestly, I'd love to have my hands on a terabyte drive with 1TBps speeds.

Memory access latency is already the biggest bottleneck when it comes to optimization, both disk and RAM.

Re: Researchers achieve optical data transmission speed of 44.2 terabits per second

#46

Post by dasudasu » Sat, May 23, 2020, 5:00 PM UTC

bobajeff wrote: post #5

I like like the bottle neck in the future will be Harddrive/SSD file read/write speeds. Honestly, I'd love to have my hands on a terabyte drive with 1TBps speeds.

Electro-optic conversion is expensive in terms of power, so you better be sure it's necessary. There are still some people looking at hybrid computers with both optics and electronics. To be practical, you'd need both to be realized in the same platform, but they don't exactly work on the same scales, and laser integration is a big issue.

Re: Researchers achieve optical data transmission speed of 44.2 terabits per second

#47

Post by 6510 » Sat, May 23, 2020, 5:02 PM UTC

PopeDotNinja wrote: post #4

And even it that speed, I bet pre-roll ads on videos still end up buffering.

Yes, we will find ways to spoil the gains arguing it doesn't matter.

Re: Researchers achieve optical data transmission speed of 44.2 terabits per second

#48

Post by dasudasu » Sat, May 23, 2020, 5:03 PM UTC

keenmaster wrote: post #21

Is anyone knowledgable on the implications of the underlying tech once it gets commercialized? Obviously things like game streaming would be improved.

This would never be for a home access point. This would be used for long-haul communications (i.e. between metro areas). The data rates there are already pretty ludicrous. The current standard is called 800G, for 800 Gbit/s per wavelength.

Re: Researchers achieve optical data transmission speed of 44.2 terabits per second

#49

Post by 6510 » Sat, May 23, 2020, 5:03 PM UTC

thejynxed wrote: post #34

throwawaygh wrote: post #23

Earlier quoted context omitted.

We will be able to make comments complaining about bloated JavaScript libraries at lightning speed.

You aren't kidding, the bloated JavaScript libraries will make my browsing session feel like a blistering 55.6k bps instead of the piddly 11.4k bps they do now.

For a while at least.

Re: Researchers achieve optical data transmission speed of 44.2 terabits per second

#50

Post by cycomanic » Sat, May 23, 2020, 5:08 PM UTC

dasudasu wrote: post #41

It is not particularly hard to do a "hero" experiment like this. Shannon limits to fiber transmission have pretty much been reached experimentally a long time ago. Muxing several wavelengths together is also of course the backbone of fiber optics transmission since its very origin. The current buzz in the field is to use micro-combs like they did as opposed to an array of lasers to provide the multiple wavelengths -…

I agree with you that microcombs come with their specific kind of challenges (and SNR is the big one), however making many semiconductor lasers so small as too fit 100 on a single chip poses lots of challenges (in particular thermal management and wavelength stability). That said, combs (not necessarily microcombs) over opportunities for additional functionality/optimizations. Because the comb lines are locked to each other (normally individual lasers have small wavelength fluctuations) let's you space channels even closer together, as well as process multiple channels at the same time.

Regarding your comment about these hero experiments not being hard, I would argue it's actually the other way around, we are now so close to the limits that it is becoming incredibly hard to observe further gains. Also regarding not modulating lines independently, this is the common way how everyone (even the industry labs) demonstrates these systems, using 100 independent transceivers would be prohibitevely expensive, moreover research has shown that you actually receive a penalty from using this approach so the demonstration is a lower bound on what could be achieved with individual tx modules.