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Researchers achieve optical data transmission speed of 44.2 terabits per second

independent.co.uk

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

#51

Post by monocasa »

YayamiOmate wrote: post #22
amelius wrote: post #6

This is not directly internet related. The original title is better: > Ultra-dense optical data transmission over standard fibre with a single chip source As a compromise, I'd propose: > 44.2 terabit/s optical data transmission over standard fibre with a single chip source

Much better, because what the heck is "internet speed". The most sensible definition to me is payload over IP protocol possibly on an existing commercial link. That's the only way I see relation to internet and the internet.

IDK, I get it. WAN backbone rates over a single fiber rather than more typical LAN rates.

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

#52

Post by cycomanic »

ganzuul wrote: post #32

I have this funny idea about a waveguide interconnect, where MIMO radios address each other inside the manifold. You could get pretty decent bus width through e.g QAM and with beam steering probably simultaneous data links. Of course it could be made to look cool as hell, complex microwave plumbing with integrated heatsink replacing a plain old mainboard. :)

This has actually been a big research topic over the last 8 years or so. The keywords are space division multiplexing (SDM) and in particular Mode division multiplexing (MDM)

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

#53

Post by sollewitt »

thejynxed wrote: post #37
z3t4 wrote: post #14

Earlier quoted context omitted.

In Sweden we have 10Gbe consumer Internet for $40/month

To be fair, here we have some counties as large as Sweden with fewer people living in them.

Sweden is the size of California.

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

#54

Post by 6510 »

postingawayonhn wrote: post #18
notaplumber wrote: post #10

Earlier quoted context omitted.

Yeah, this confuses me. Gigabit is available in several places in North America. I had to check the date on the article.. posted 20 hours ago. Yep. Still confused.

> where the average download speed is 197.3 megabits per second (mbps). Average is the key word there. Higher speeds may be available but just not used by many people die to cost. In New Zealand for example 95% of the population has access to gigabit (with 10 gigabit being tested in places) speeds but the average download speed is only around 50 mbps due to most people opting for slower/cheaper plans.

My ISP in the Netherlands made slow plans only a few euro cheaper than fast ones. 50 mbit = 46.50, 250 mbit = 56.50, 500 mbit = 64.50, 1000 mbit = 76.50

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

#55

Post by dasudasu »

billme wrote: post #40
detaro wrote: post #35

Earlier quoted context omitted.

This is a field that's constantly being worked on, not sure why you say there isn't a "push" in it. This specific thing is not faster than previous results, but more compact. Long-distance fiber lines also have amplifiers along the way, so you can't just scale them up by changing the endpoints if it doesn't match the capability of the in-line hardware.

Cost of swapping the amplifiers, not just the end-points, makes sense as an issue. Thanks! As for it being “only more compact” not a capacity increase, for a comparable single coherent optical fiber line, are existing fibers filled to capacity due to the limits of tech, economies, physics, etc. - if physics, then I assume all fibers are at capacity, right?

If you're going to lay a fiber across the oceans, then yeah, that capacity is going to approach the Shannon limit, but at some point there is a calculation to be made about how expensive it is to use all that capacity vs using multi-core fibers or just laying out more fibers.

The economics of it are pretty interesting. A single fiber (non-submarine) is about ¢8 a meter in raw cost, and it said that they laid out so many during the telecom bubble of the late 1990s that there are still many unused (so-called dark) fiber networks throughout the US. See for example https://www.ofsoptics.com/lighting-up-dark-fiber/

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

#56

Post by cycomanic »

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.

The research here is all about core and metro networks, so those are the networks connecting metropolitan areas to each other and the ones connecting the big users within metro areas. The home users and mobile users are not directly connected to these networks, but through e.g. your providers passive optical network. You can think about this similar to a road network, you are living on the little side roads, these are the big highways and ring roads. But because everyone is using more and more data on their home and mobile devices, there needs to be bigger pipes in the core network (despite more and more local data centres for caching)

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

#57

Post by dasudasu »

cycomanic wrote: post #50
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 eac…

Modulating individual lines is the only way for such a scheme to become practical in a real environment and achieve the claimed data rates. Making hundreds of modulators and receivers fit within a single chip is about as hard as making hundreds of laser fit a single chip, hence why it's not realistically being pursued by the industry. My point is that if you already require separate chips for the rest of the transceiver, integrating the laser itself becomes much less of an issue, and the benefits of a single laser source common to all much more muted.

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

#58

Post by cycomanic »

detaro wrote: post #35
billme wrote: post #28

Given the cost of laying fiber lines across the ocean and this tech (appears) to double the capacity of an existing line, why would there not be a push to get this into use, what am I missing?

This is a field that's constantly being worked on, not sure why you say there isn't a "push" in it. This specific thing is not faster than previous results, but more compact. Long-distance fiber lines also have amplifiers along the way, so you can't just scale them up by changing the endpoints if it doesn't match the capability of the in-line hardware.

That is incorrect the amplifiers have the capacity to amplify lots of channels simultaneously. So it is sufficient to only upgrade the endpoints (unless your fibre is full, where full means the bandwidth of the amplifiers, ~100 Tb/s for a single fibre). This has in fact been the driver behind the tremendous growth in data rates we have seen in the last 30 years. Operators can incrementally upgrade links by upgrading the endpoints. To transfer a MB across the network was 100s of $ in the 90s and is now essentially free (it's like 10e-4 cents or sol
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