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The key point is the petabit per second rate they achieved: >Using only a single light source, scientists have set a world record by transmitting 1.8 petabits

The key point is the petabit per second rate they achieved: >Using only a single light source, scientists have set a world record by transmitting 1.8 petabits per second. In 2021 the world record was 300 TB[0]. Why is the headline misleading? for reference, the headline is currently "Record-breaking chip can transmit entire internet's traffic per second." This seems to be correct: >According to a study from global telecommunications market research and consulting firm TeleGeography, global internet bandwidth has risen by 28% over the course of 2022, with a four-year compound annual growth rate (CAGR) of 29%, and is now standing at 997Tbps (terabits per second).[1] >Normally, data over a fiber is multiplexed using many wavelengths of light (wave-division multiplexing, or WDM for short). These wavelengths are generated from an array of lasers, forming a frequency comb. I think that is a relativly new techniuque. For example see https://www.nature.com/articles/s41467-019-14010-7 https://www.nature.com/articles/s41467-019-14010-7 : >Optical frequency combs were originally conceived for establishing comparisons between atomic clocks1 and as a tool to synthesize optical frequencies2,3, but they are also becoming an attractive light source for coherent fiber-optical communications, where they can replace the hundreds of lasers used to carry digital data So "normally" might give the wrong impression. As far as I know, no commercial service is using it. One reason is the cost, which this article addresses by proposing a chip based apporach which makes it cheaper and easier. [0]https://www.nict.go.jp/en/press/2021/07/12-1.html https://www.nict.go.jp/en/press/2021/07/12-1.html [1]https://www.computerweekly.com/news/252524883/New-networking-era-imminent-as-global-internet-bandwidth-rises-28-in-2022 https://www.computerweekly.com/news/252524883/New-networking... Edit: I should point out that the "previous" record was with a 4-core optical fiber, whereas this one uses a 37 core one. They are really two different things: one about the cable and the other about the transmitter. So this one doesn't "beat" the other.

formerly_proven 4y ago
Maybe I'm missing a nuance here but WDM with one laser per wavelength is bread and butter tech used everywhere. The base case (n=2) even forms the basis of PON networks.
- Vt71fcAqt7 4y ago
  Frequency combs are derived from a single light source. >Current fibre optic communication systems owe their high-capacity abilities to the wavelength-division multiplexing (WDM) technique, which combines data channels running on different wavelengths, and most often requires many individual lasers. Optical frequency combs, with equally spaced coherent comb lines derived from a single source, have recently emerged as a potential substitute for parallel lasers in WDM systems[0](2021) So "These wavelengths are generated from an array of lasers, forming a frequency comb" is using "frequency comb" to mean something else in that sentence. [0]https://www.degruyter.com/document/doi/10.1515/nanoph-2020-0561/html https://www.degruyter.com/document/doi/10.1515/nanoph-2020-0...
  - jpmattia 4y ago
    > So "These wavelengths are generated from an array of lasers, forming a frequency comb" is using "frequency comb" to mean something else in that sentence. Yes, "frequency grid" would have been better terminology. Common spacing for WDM is 50 GHz between adjacent frequencies (it's ITU spec'd iirc), and those rely on feedback system to maintain the spacing precision.
jpmattia 4y ago
> Why is the headline misleading? for reference, the headline is currently "Record-breaking chip can transmit entire internet's traffic per second." The "chip" is a CW laser, so it transmits no data. It's a little hard to tell from the article + PR, but I think the result is a laser with a stabilized frequency-comb output suitable for WDM that has been implemented on a single die (which is still a nice result.) Perhaps I missed that they implemented an entire transmitter chain on the "chip", but I believe the chip innovation is the continuous photon source, not the data transmission.
- henrikeh 4y ago
  The chip which produced the laser is indeed “just” CW with data modulated on separately. And novelty indeed lies in the width of the comb source and the SNRs of the obtained channels. (Worked on this project.)
  - jpmattia 4y ago
    Congrats to you and team on these results. > And novelty indeed lies in the width of the comb source and the SNRs of the obtained channels. Can you expand on this? I'd be curious how it compares to a traditional (multi-laser) WDM system, probably others would be too.
    - henrikeh 4y ago
      Thanks! I’ve reached out to my colleague who worked on the chip side of this project.
- Caspy7 4y ago
  Ok, so this is one step in such hyper-fast data transmission. What would be the other hurdles?

formerly_proven 4y ago

Maybe I'm missing a nuance here but WDM with one laser per wavelength is bread and butter tech used everywhere. The base case (n=2) even forms the basis of PON networks.

Vt71fcAqt7 4y ago
Frequency combs are derived from a single light source. >Current fibre optic communication systems owe their high-capacity abilities to the wavelength-division multiplexing (WDM) technique, which combines data channels running on different wavelengths, and most often requires many individual lasers. Optical frequency combs, with equally spaced coherent comb lines derived from a single source, have recently emerged as a potential substitute for parallel lasers in WDM systems[0](2021) So "These wavelengths are generated from an array of lasers, forming a frequency comb" is using "frequency comb" to mean something else in that sentence. [0]https://www.degruyter.com/document/doi/10.1515/nanoph-2020-0561/html https://www.degruyter.com/document/doi/10.1515/nanoph-2020-0...
- jpmattia 4y ago
  > So "These wavelengths are generated from an array of lasers, forming a frequency comb" is using "frequency comb" to mean something else in that sentence. Yes, "frequency grid" would have been better terminology. Common spacing for WDM is 50 GHz between adjacent frequencies (it's ITU spec'd iirc), and those rely on feedback system to maintain the spacing precision.

jpmattia 4y ago

> Why is the headline misleading? for reference, the headline is currently "Record-breaking chip can transmit entire internet's traffic per second." The "chip" is a CW laser, so it transmits no data. It's a little hard to tell from the article + PR, but I think the result is a laser with a stabilized frequency-comb output suitable for WDM that has been implemented on a single die (which is still a nice result.) Perhaps I missed that they implemented an entire transmitter chain on the "chip", but I believe the chip innovation is the continuous photon source, not the data transmission.

henrikeh 4y ago
The chip which produced the laser is indeed “just” CW with data modulated on separately. And novelty indeed lies in the width of the comb source and the SNRs of the obtained channels. (Worked on this project.)
- jpmattia 4y ago
  Congrats to you and team on these results. > And novelty indeed lies in the width of the comb source and the SNRs of the obtained channels. Can you expand on this? I'd be curious how it compares to a traditional (multi-laser) WDM system, probably others would be too.
  - henrikeh 4y ago
    Thanks! I’ve reached out to my colleague who worked on the chip side of this project.
Caspy7 4y ago
Ok, so this is one step in such hyper-fast data transmission. What would be the other hurdles?