Why do you think 100gbps+ is not feasible for sat to sat lasers? The vacuum of space is a better environment than 500km of glass with a bunch of inline repeaters.
Because a few discrete OOK lasers in a single frequency aiming at another moving target, while they will have a lot of capacity compared to an rf link, will have a minuscule amount of capacity in Gbps compared to a whole DWDM based, coherent 100GbE+ optical transport system operating on singlemode fiber.
Like, literally, twenty or thirty individual full duplex 400GbE circuits in two strands of fiber, if you have enough money to throw at the problem.
The only way you could approach matching the same capacity on a sat to sat link would be if you had a massive array of 30-40 separate laser tx and corresponding massive array of 30-40 rx receptors on the other side. It's easier to understand if you've seen a DWDM mux and demux in person in a telecom facility.
I'd like to be proven wrong if somebody can do multi Tbps of capacity on a sat to sat laser link, that would be awesome, but the challenges are very high.
> The only way you could approach matching the same capacity on a sat to sat link would be if you had a massive array of 30-40 separate laser tx and corresponding massive array of 30-40 rx receptors on the other side.
This does sound like the sort of thing Musk would try, especially post-Starship, if the rest of the setup was physically possible.
One of the other problems is that the ultimate last hop for data would still have to be an rf link satellite to earth station through atmosphere, where lasers don't work well at all (there's a rain and junk in the air reason the telecom industry has given up on free space optics lasers for 1-2km, 1 to 20Gbps data links roof to roof and uses millimeter wave fdd radios instead)
Two satellites from the same launch, in the same orbital inclination, following each other in a conga line of starlink satellites are still slightly moving relative to each other, considering the narrow beam width of a laser shot at distances of 50 to 80 km or more between satellites.
