6 ms·

Note here that "faster" here really means more speed and not an increase in the volume of data transferred : The light go through the air hollow-core so can go

Note here that "faster" here really means more speed and not an increase in the volume of data transferred : The light go through the air hollow-core so can go at near "c" (the speed of light in vacuum) speed, instead of being constrained to "speed of light in glass which is only "2/3 c". This allows reduce latency for long distance communication. https://spie.org/news/photonics-focus/julyaug-2022/speeding-light-with-hollow-core-fibers https://spie.org/news/photonics-focus/julyaug-2022/speeding-...

hyperhello 1y ago
So submarine cables were limited to 0.67c and now aren’t? Can this really work?
- p_j_w 1y ago
  > So submarine cables were limited to 0.67c and now aren’t? I think it’s more like in the future they might not be. It’s anyone’s guess how mass production and deployment of this might look.
- b3orn 1y ago
  For submarine cables there are two things here. The first is lower attenuation which allows for fewer amplifiers along the route making it overall cheaper. The second is lower latency. There have been cases where high frequency trading people went wireless to get lower latency because of the higher propagation speed of EM-waves in air. For really long distances you can go theoretically use satellite links to get lower latency than a submarine cable even if the total distance increases.
  - Figs 1y ago
    Someday, someone is finally going to work out how to do comms with neutrinos (which can pass directly through the Earth and come out the other side) and make so much money...
    - cryptonector 1y ago
      They are not, for the thing that would make neutrinos useful for communications is also the thing that makes them useless for communications. In order to use them for comms you'd need to produce such a huge number of neutrinos, and/or in a very colimated beam, that one shudders to think of how one might produce them!
      - Figs 1y ago
        I suspect it may be possible using neutrino-antineutrino annihilation if there's a good way to produce streams of both types of particles, but... physics isn't my field.
      - benlivengood 1y ago
        I think you could moderate a large nuclear fission reactor (on the edge of criticality) to produce detectable differences in neutrino rate on the other side of the world. KamLAND and a few other experiments detected multi-GW reactor anti neutrinos at 1000km[0] and so presumably tens of GW (easily [if perhaps not safely?] achievable briefly in current reactors) should be detectable over 8000km. [0] https://www.sciencedirect.com/science/article/pii/S1738573316000498 https://www.sciencedirect.com/science/article/pii/S173857331...
Sesse__ 1y ago
It's true, but for most cases, the volume of a fiber is not the problem anyway. Latency is a problem most of us somehow bump into every day, while most fibers in the ground are nowhere near what you can push out of DWDM (e.g., off-the-shelf equipment will easily allow you to run 20x100Gbit over a single fibre, but many of them only carry a single 10Gbit or even 1Gbit link). Trans-continental is different, because you'll need amplifiers. Many, many amplifiers in a row. And those generally work well only in a fairly limited band. But unless you're doing submarine, bandwidth is almost never the problem. To make things worse, a lot of existing medium-haul fiber links are actually twice as long as you'd expect, due to the desire to cancel out dispersion; you first run the fiber e.g. 10km from place to place, and then run it through a large 10km spool (of a slightly different type of fiber) in the datacenter to cancel out the dispersion. This is slowly going away, but only slowly.
- xeonmc 1y ago
  does using hollow core means you can do away with dispersion compensation?
  - Sesse__ 1y ago
    AFAIK yes, but if that's your goal, a far easier solution is to just use transmission standards that don't care about dispersion (coherent detection). E.g., all 100gig transmission already does not care about it.
- Joel_Mckay 1y ago
  Sounds like it was something like CML for >200km runs. =3
- Hikikomori 1y ago
  >To make things worse, a lot of existing medium-haul fiber links are actually twice as long as you'd expect, due to the desire to cancel out dispersion; you first run the fiber e.g. 10km from place to place, and then run it through a large 10km spool (of a slightly different type of fiber) in the datacenter to cancel out the dispersion. This is slowly going away, but only slowly. Only slowly? I haven't worked with very long haul wdm systems or sonet/sdh but I've never seen this. Maybe you mean much longer distances than 10km as we've had 10G-LR for ages that don't need this.
PetitPrince 1y ago
Thanks for your precision. Off-topic: It's true that "faster Internet" means "bigger Internet" in common language, just like in photography "faster lens" means "lens with more light gathering capability". I wonder if there's other field where "faster" is misused.
- lazide 1y ago
  Higher bandwidth means less time to transmit a given packet. Just like more light gathering in a lens allows faster shutter speeds. If you had to move 100 tons of packages, which is going to be faster - a Lamborghini going 200 mph, or a tractor/trailer going 50mph? If you’re trying to set a speed record and don’t care about bringing anything along, which is faster? Neither meaning is necessarily wrong.
  - gchamonlive 1y ago
    Even if directly it isn't technically right to say it's faster, but with it's applications built upon such technology it manifests in these tasks being done faster. Makes sense. And the time for the lambo and the tractor will depend on the round trips each will have to do, so it depends on the medium.
davidkuennen 1y ago
This is actually much more important than the volume of data transferred. Having 33% lower latencies across the globe would be huge.
- crote 1y ago
  On the other hand, it is only 33% - and that is an upper bound. Getting data to literally the other side of the globe currently takes about 100 milliseconds. How many truly novel applications open up by that latency dropping to 66ms? For short-distance stuff the latency is already low enough to be practically realtime. For long-distance stuff we're already fast enough for human-level applications (like video chat), but it's not dropping enough for computer-level applications (like synchronous database replication). I'm sure some HFT traders are going to make an absolute fortune, but I doubt it'll have a huge impact for most other people.
  - notimetorelax 1y ago
    I generally agree with you, but! Video or audio calls between EU and the US still have a much higher chance of speaking up at the same time and it’s due to lag. If the latency is decreased by 33% it might be a game changer.
  - batmansmk 1y ago
    I made my master thesis on real-time, with a chapter where I experimented with different levels of jitter and latency. Jitter is the consistency of the latency, is it like a locked 66ms or sometimes does it go to 200ms. Jitter is more impactful than latency for a wide range of applications, from gaming to music and video call. Having a lower latency allows for lower jitter, or less jitter while keeping the same latency. Today’s discovery is huge imo.
    - lillecarl 1y ago
      Doesn't jitter come from the switches and routers along the path? I have a hard time seeing a fibre having significant jitter.
    - 1y ago

hyperhello 1y ago

So submarine cables were limited to 0.67c and now aren’t? Can this really work?

p_j_w 1y ago
> So submarine cables were limited to 0.67c and now aren’t? I think it’s more like in the future they might not be. It’s anyone’s guess how mass production and deployment of this might look.
b3orn 1y ago
For submarine cables there are two things here. The first is lower attenuation which allows for fewer amplifiers along the route making it overall cheaper. The second is lower latency. There have been cases where high frequency trading people went wireless to get lower latency because of the higher propagation speed of EM-waves in air. For really long distances you can go theoretically use satellite links to get lower latency than a submarine cable even if the total distance increases.
- Figs 1y ago
  Someday, someone is finally going to work out how to do comms with neutrinos (which can pass directly through the Earth and come out the other side) and make so much money...
  - cryptonector 1y ago
    They are not, for the thing that would make neutrinos useful for communications is also the thing that makes them useless for communications. In order to use them for comms you'd need to produce such a huge number of neutrinos, and/or in a very colimated beam, that one shudders to think of how one might produce them!
    - Figs 1y ago
      I suspect it may be possible using neutrino-antineutrino annihilation if there's a good way to produce streams of both types of particles, but... physics isn't my field.
    - benlivengood 1y ago
      I think you could moderate a large nuclear fission reactor (on the edge of criticality) to produce detectable differences in neutrino rate on the other side of the world. KamLAND and a few other experiments detected multi-GW reactor anti neutrinos at 1000km[0] and so presumably tens of GW (easily [if perhaps not safely?] achievable briefly in current reactors) should be detectable over 8000km. [0] https://www.sciencedirect.com/science/article/pii/S1738573316000498 https://www.sciencedirect.com/science/article/pii/S173857331...

Sesse__ 1y ago

It's true, but for most cases, the volume of a fiber is not the problem anyway. Latency is a problem most of us somehow bump into every day, while most fibers in the ground are nowhere near what you can push out of DWDM (e.g., off-the-shelf equipment will easily allow you to run 20x100Gbit over a single fibre, but many of them only carry a single 10Gbit or even 1Gbit link). Trans-continental is different, because you'll need amplifiers. Many, many amplifiers in a row. And those generally work well only in a fairly limited band. But unless you're doing submarine, bandwidth is almost never the problem. To make things worse, a lot of existing medium-haul fiber links are actually twice as long as you'd expect, due to the desire to cancel out dispersion; you first run the fiber e.g. 10km from place to place, and then run it through a large 10km spool (of a slightly different type of fiber) in the datacenter to cancel out the dispersion. This is slowly going away, but only slowly.

xeonmc 1y ago
does using hollow core means you can do away with dispersion compensation?
- Sesse__ 1y ago
  AFAIK yes, but if that's your goal, a far easier solution is to just use transmission standards that don't care about dispersion (coherent detection). E.g., all 100gig transmission already does not care about it.
Joel_Mckay 1y ago
Sounds like it was something like CML for >200km runs. =3
Hikikomori 1y ago
>To make things worse, a lot of existing medium-haul fiber links are actually twice as long as you'd expect, due to the desire to cancel out dispersion; you first run the fiber e.g. 10km from place to place, and then run it through a large 10km spool (of a slightly different type of fiber) in the datacenter to cancel out the dispersion. This is slowly going away, but only slowly. Only slowly? I haven't worked with very long haul wdm systems or sonet/sdh but I've never seen this. Maybe you mean much longer distances than 10km as we've had 10G-LR for ages that don't need this.

PetitPrince 1y ago

Thanks for your precision. Off-topic: It's true that "faster Internet" means "bigger Internet" in common language, just like in photography "faster lens" means "lens with more light gathering capability". I wonder if there's other field where "faster" is misused.

lazide 1y ago
Higher bandwidth means less time to transmit a given packet. Just like more light gathering in a lens allows faster shutter speeds. If you had to move 100 tons of packages, which is going to be faster - a Lamborghini going 200 mph, or a tractor/trailer going 50mph? If you’re trying to set a speed record and don’t care about bringing anything along, which is faster? Neither meaning is necessarily wrong.
- gchamonlive 1y ago
  Even if directly it isn't technically right to say it's faster, but with it's applications built upon such technology it manifests in these tasks being done faster. Makes sense. And the time for the lambo and the tractor will depend on the round trips each will have to do, so it depends on the medium.

davidkuennen 1y ago

This is actually much more important than the volume of data transferred. Having 33% lower latencies across the globe would be huge.

crote 1y ago
On the other hand, it is only 33% - and that is an upper bound. Getting data to literally the other side of the globe currently takes about 100 milliseconds. How many truly novel applications open up by that latency dropping to 66ms? For short-distance stuff the latency is already low enough to be practically realtime. For long-distance stuff we're already fast enough for human-level applications (like video chat), but it's not dropping enough for computer-level applications (like synchronous database replication). I'm sure some HFT traders are going to make an absolute fortune, but I doubt it'll have a huge impact for most other people.
- notimetorelax 1y ago
  I generally agree with you, but! Video or audio calls between EU and the US still have a much higher chance of speaking up at the same time and it’s due to lag. If the latency is decreased by 33% it might be a game changer.
- batmansmk 1y ago
  I made my master thesis on real-time, with a chapter where I experimented with different levels of jitter and latency. Jitter is the consistency of the latency, is it like a locked 66ms or sometimes does it go to 200ms. Jitter is more impactful than latency for a wide range of applications, from gaming to music and video call. Having a lower latency allows for lower jitter, or less jitter while keeping the same latency. Today’s discovery is huge imo.
  - lillecarl 1y ago
    Doesn't jitter come from the switches and routers along the path? I have a hard time seeing a fibre having significant jitter.
  - 1y ago