Optical inter-satellite links (OISLs) use laser beams to transmit data between satellites at rates of 10-100+ Gbps, far exceeding the capacity of traditional radio frequency crosslinks. Starlink's second-generation satellites are equipped with laser crosslinks that allow data to hop between satellites in orbit, routing traffic around the globe without touching the ground until it reaches the nearest gateway to the destination.
OISLs are transformative because they decouple constellation routing from ground station placement. A user in a remote ocean location can have their traffic relayed through a chain of satellite-to-satellite laser hops to a gateway on a different continent, dramatically reducing latency compared to traditional satellite architectures. The technology also has no spectrum licensing constraints since laser beams in space do not interfere with terrestrial or other satellite radio systems.