Editing Last mile (telecommunications) (section)

====Lightwaves and free-space optics====
Visible and infrared light waves are much shorter than radio frequency waves. Their use to transmit data is referred to as [[free-space optical communication]]. Being short, light waves can be focused or collimated with a small lens/antenna, and to a much higher degree than radio waves. Thus, a receiving device can recover a greater portion of the transmitted signal.

Also, because of the high frequency, a high [[Bit rate|data transfer rate]] may be available. However, in practical last mile environments, obstructions and de-steering of these beams, and absorption by elements of the atmosphere including fog and rain, particularly over longer paths, can greatly restrict their use for last-mile wireless communications.