Japan Shatters Internet Speed Record at 319 tb/s | Hacker News Reader

Japan Shatters Internet Speed Record at 319 tb/s

interestingengineering.com

83 pointskjeetgill7 comments

From the Paper: We report the first experimental demonstration of transoceanic distance real-time transmission over coupled multicore fibers. The WDM DP-QPSK signals were transmitted over 7,200-km coupled-core four-core fibers by a recirculating loop and demodulated by real-time MIMO DSP.

From the headline I'd feared it was just about a new technology still in the lab but it looks like they've already tested it fro transoceanic cables.

I'd imagine this means more for island nations like Japan and Australia's overall bandwidth than anything towards consumer internet speeds.

Just because it was 7.2 megameters, a "transoceanic distance", doesn't mean it wasn't just 7.2 megameters of fiber all coiled up in a lab room.

I'd expect the capability of creating thin enough fiber that you could coil 7.2Mm of it in a single reasonably-sized room, would be quite an achievement in its own

I’ve never worked with fiber optics but I wonder if that’s the point of the recirculating loop i.e. use a shorter fiber but run the signal through it multiple times to simulate a longer length.

Or delay line storage, it would store 7.6 TB.

Could someone explain what exactly is new here? WDM and DP-QPSK isn't new.

>The new system begins its transmission process with a 552-channel comb laser

> The signal runs through two novel kinds of fiber amplifiers, one doped in thulium, the other in erbium, before it continues on its way, in a conventional process called Raman amplification.

I am guessing the 552 channel is a new record, and the Amplifier is the new thing here?

I would also like to know what are the current speed per single core of fibre in use for long distance under sea cables? Most only quote the whole undersea cable without mentioning how many cores. And without it, it is hard to tell whether 319 Tbps is comparatively speaking a large increase. For example the purposed Pacific Light Cable from LA to HK is 144 Tbps.

I am also far more interested in the Ultra Low Latency Cable where light travel at close to max speed rather than 2/3 of its speed within fibre. Unfortunately it seems nothing much happening in that area.

I've already posted the link to the original news: https://news.ycombinator.com/item?id=27818357

Reply on news.ycombinator.com