Most fiber connections offer far greater bandwidth than microwave links. One reason is that fiber uses light instead of the much longer wavelength employed in microwave radio systems. What if it were possible to use light to send data between satellites, instead of relying on scarce microwave frequencies? That’s exactly what researchers at Germany’s Fraunhofer Institute for Laser Technology demonstrated by establishing a laser link between German satellite TerraSAR-X and the U.S. satellite NFIRE over a distance in space of more than 5,000 kilometers. Data was transferred without any errors. The Fraunhofer Institute research news article Satellite communications by laser said the data was exchanged at data rates 100 times greater than could be achieved using radio frequencies.
Another advantage to using lasers instead of RF is laser beams can be more tightly focused, reducing interference and the chance of interception. While the article focuses on communication between satellites, it appears the technology may have some use in terrestrial links as well.
