Frequency matters; masers are much more challenging than lasers, for example. But in any case, a direct laser link can carry enormous amounts of data. Even indi

Frequency matters; masers are much more challenging than lasers, for example. But in any case, a direct laser link can carry enormous amounts of data. Even indirect LED transmission has been shown to viably carry many Gb/s. The challenge, of course, is the aim. It's not that easy to hit a pea that's several thousand of km away. I imagine feedback aiming systems where the vessels steer each other's transmitters, but that requires some amount of surface area for reception and that part doesn't scale as easily as fibers do.