5 ms·

> require a generational shift to deploy. Photonic bandgap / Bragg fiber is being produced in quantity, and some subsea cables are using it. I'm pretty sure i

> require a generational shift to deploy. Photonic bandgap / Bragg fiber is being produced in quantity, and some subsea cables are using it. I'm pretty sure it's the satellite lasers that require the generational shift. One subsea cable has no bearing on any other; once the first is installed, you're up and running. not so with laser-connected swarms.

ortusdux 3y ago
Starlink's laser connections have been active for a year now.
- cma 3y ago
  What's the latency NY to Australia all over Starlink with laser interconnect now?
  - modeless 3y ago
    I don't know if Starlink is routing packets that way. I think it's more likely that they route packets to a ground station as soon as possible to save laser link capacity for customers that actually need it, like ones in the middle of the ocean. If you want your packets routed all the way around the Earth through space then you'd probably need a special contract with SpaceX.
- thesz 3y ago
  [1] https://wccftech.com/starlink-turns-on-laser-satellites-for-region-with-fourth-month-long-night/ https://wccftech.com/starlink-turns-on-laser-satellites-for-... Judging from [1], lasers are used not for inter-satellite links, but for downstream or upstream links - from satellites to the ground. Intersatellite links require precise machinery, such as picometer-precise positioning systems [2]. [2] https://www.pi-usa.us/fileadmin/user_upload/pi_us/files/product_datasheets/P363_Pico-Positioning_Piezo_Stage.pdf https://www.pi-usa.us/fileadmin/user_upload/pi_us/files/prod... Also, there should be compensation for satellite rotation, initial targeting and tracking. At ~12km between satellites (~4000 on 550 km orbit), the (possible) target of laser signal receiver which, say, is one meter in diameter will be one third of an angular minute. It is not impossible to target that initially, but keep in mind that laser beam is very focused and its power drops significantly with the angular distance. I really do not know how to even target satellites' receivers initially, let alone compensate for rotation and track these targets afterwards.
  - ortusdux 3y ago
    From [1]: "Space lasers allow Starlink satellites to connect directly to one another, eliminating the need for a local ground station and enabling Starlink. to deliver service to some of the most remote locations in the world - like Antarctica."
  - wmf 3y ago
    Don't read WCCFTech; they don't know what they're talking about. AFAIK the satellites within an orbital plane are stationary relative to each other, so once the laser is aimed it should stay connected.
cycomanic 3y ago
Photonic bandgap fibres are not used in submarine cables their loses are too high. There are recent antiresonant fibres (NANF) which can achieve lower losses than even SMF. However production capabilities are not ready yet to make the amount of fibre necessary for submarine. The startup (out of Southampton) that pioneered these was recently acquired by Microsoft. We probably see these fibres for links between the exchange and data centres first (although there it is difficult to beat RF links, as they are direct line of sight)

ortusdux 3y ago

Starlink's laser connections have been active for a year now.

cma 3y ago
What's the latency NY to Australia all over Starlink with laser interconnect now?
- modeless 3y ago
  I don't know if Starlink is routing packets that way. I think it's more likely that they route packets to a ground station as soon as possible to save laser link capacity for customers that actually need it, like ones in the middle of the ocean. If you want your packets routed all the way around the Earth through space then you'd probably need a special contract with SpaceX.
thesz 3y ago
[1] https://wccftech.com/starlink-turns-on-laser-satellites-for-region-with-fourth-month-long-night/ https://wccftech.com/starlink-turns-on-laser-satellites-for-... Judging from [1], lasers are used not for inter-satellite links, but for downstream or upstream links - from satellites to the ground. Intersatellite links require precise machinery, such as picometer-precise positioning systems [2]. [2] https://www.pi-usa.us/fileadmin/user_upload/pi_us/files/product_datasheets/P363_Pico-Positioning_Piezo_Stage.pdf https://www.pi-usa.us/fileadmin/user_upload/pi_us/files/prod... Also, there should be compensation for satellite rotation, initial targeting and tracking. At ~12km between satellites (~4000 on 550 km orbit), the (possible) target of laser signal receiver which, say, is one meter in diameter will be one third of an angular minute. It is not impossible to target that initially, but keep in mind that laser beam is very focused and its power drops significantly with the angular distance. I really do not know how to even target satellites' receivers initially, let alone compensate for rotation and track these targets afterwards.
- ortusdux 3y ago
  From [1]: "Space lasers allow Starlink satellites to connect directly to one another, eliminating the need for a local ground station and enabling Starlink. to deliver service to some of the most remote locations in the world - like Antarctica."
- wmf 3y ago
  Don't read WCCFTech; they don't know what they're talking about. AFAIK the satellites within an orbital plane are stationary relative to each other, so once the laser is aimed it should stay connected.

cycomanic 3y ago

Photonic bandgap fibres are not used in submarine cables their loses are too high. There are recent antiresonant fibres (NANF) which can achieve lower losses than even SMF. However production capabilities are not ready yet to make the amount of fibre necessary for submarine. The startup (out of Southampton) that pioneered these was recently acquired by Microsoft. We probably see these fibres for links between the exchange and data centres first (although there it is difficult to beat RF links, as they are direct line of sight)