The idea of sending data through a modulated laser beam is not new. It was first tried in the 1980s, with embarrassing results. The beams had to be so tightly focused that even buildings swaying in the wind could dislodge them, and customers feared being zapped by a misconfigured beam. A new generation of lasers boasts higher speeds than microwave, and may eventually even displace fiber.
Fiber networks are able to reach such high capacities because they use spectrum in the optical region, including infrared and visible light. The frequencies of these are measured in hundreds of terahertz, so a very small slice can give a higher bandwidth than the entire radio region.
With bandwidth to spare, there is no need for TDMA, ...