4 ms·

> They are 50% faster No, pretty sure light still travels through them at C. What they can do is carry more data, largely by having lower error rates.

theideaofcoffee 4y ago
'c' is dependent on the medium. The value of c as it is commonly known, 300 million meters per second, is in vacuum. Light traveling through other media is affected by its index of refraction, in the case of silica fiber, that is approximately 1.5 so radiation propagates much slower through silica than it does a vacuum. Since gases have low refractive indicies already, within a hundred ppm or so of a vacuum, you could essentially round air to 1.
- ortusdux 4y ago
  I've heard that high frequency traders are interested in Starlink's planned laser links because they could open up routes that are faster than traditional terrestrial fiber.
  - guipsp 4y ago
    I think that if you are a HFT, you probably have a server set up next door.
    - samwillis 4y ago
      The suggestion is about trading across multiple exchanges, for example between London and NY. Going via Starlink is potentially quicker than a fiber under the Atlantic. They will have servers “next door” to the exchanges, but need the servers to have incredible low latency connections to each other.
  - theideaofcoffee 4y ago
    Yeah, that would make sense. There are links that have been built by various HFT firms and banks [0] [1] that use microwaves instead of fiber buried in the ground simply because of this speed-of-light-in-media limitation. They can shave a few hundred nanoseconds (or something, I don't want to do the math right now) because of a higher signal propagation speed and get a trade in faster than their competitors. Same thing with a laser link like this. Edit: cf. [0] https://arstechnica.com/information-technology/2016/11/private-microwave-networks-financial-hft/ https://arstechnica.com/information-technology/2016/11/priva... [1] https://www.reuters.com/article/us-highfrequency-microwave/lasers-microwave-deployed-in-high-speed-trading-arms-race-idUSBRE9400L920130501 https://www.reuters.com/article/us-highfrequency-microwave/l...
  - cycomanic 4y ago
    I know the main people behind much of the hollow core work being done. Much of their financing is coming from HFT related firms.
maxfan8 4y ago
Light only travels at C in a vacuum (so it doesn't actually travel at C in a standard fiber optic cable, it's actually much slower).
scottlamb 4y ago
"c" is the speed of light in a vacuum. Traditional fiber optic cables are very much not a vacuum, with an index of refraction of ~1.5, so light travels through them at ~2/3c. In contrast, light actually travels at nearly c through hollow core cables.
deleted 4y ago
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idiotsecant 4y ago
It's so nice when someone other than myself is confidently incorrect.

theideaofcoffee 4y ago

'c' is dependent on the medium. The value of c as it is commonly known, 300 million meters per second, is in vacuum. Light traveling through other media is affected by its index of refraction, in the case of silica fiber, that is approximately 1.5 so radiation propagates much slower through silica than it does a vacuum. Since gases have low refractive indicies already, within a hundred ppm or so of a vacuum, you could essentially round air to 1.

ortusdux 4y ago
I've heard that high frequency traders are interested in Starlink's planned laser links because they could open up routes that are faster than traditional terrestrial fiber.
- guipsp 4y ago
  I think that if you are a HFT, you probably have a server set up next door.
  - samwillis 4y ago
    The suggestion is about trading across multiple exchanges, for example between London and NY. Going via Starlink is potentially quicker than a fiber under the Atlantic. They will have servers “next door” to the exchanges, but need the servers to have incredible low latency connections to each other.
- theideaofcoffee 4y ago
  Yeah, that would make sense. There are links that have been built by various HFT firms and banks [0] [1] that use microwaves instead of fiber buried in the ground simply because of this speed-of-light-in-media limitation. They can shave a few hundred nanoseconds (or something, I don't want to do the math right now) because of a higher signal propagation speed and get a trade in faster than their competitors. Same thing with a laser link like this. Edit: cf. [0] https://arstechnica.com/information-technology/2016/11/private-microwave-networks-financial-hft/ https://arstechnica.com/information-technology/2016/11/priva... [1] https://www.reuters.com/article/us-highfrequency-microwave/lasers-microwave-deployed-in-high-speed-trading-arms-race-idUSBRE9400L920130501 https://www.reuters.com/article/us-highfrequency-microwave/l...
- cycomanic 4y ago
  I know the main people behind much of the hollow core work being done. Much of their financing is coming from HFT related firms.

maxfan8 4y ago

Light only travels at C in a vacuum (so it doesn't actually travel at C in a standard fiber optic cable, it's actually much slower).

scottlamb 4y ago

"c" is the speed of light in a vacuum. Traditional fiber optic cables are very much not a vacuum, with an index of refraction of ~1.5, so light travels through them at ~2/3c. In contrast, light actually travels at nearly c through hollow core cables.

deleted 4y ago

[deleted]

idiotsecant 4y ago

It's so nice when someone other than myself is confidently incorrect.