Optical Free Space Communication
With the improvements in semiconductors optical free space communication has become n attractive alternative to existing signal conducts as fibre or wireless (RF). It offers high data rates and is much less expensive than underground fibre. But there are a few restrictions, which may mean it remains an alternative. Many engineers are familiar with one of two successful existing technologies for data communication:
(1) Guided wave (e.g. fibre optics) and
(2) wireless free space communication (e.g. RF). Fibre optics offers extremely high bandwidths for high data rate, while RF communications offers the advantage of wireless connectivity and the ability to broadcast over a wide area. Optical free space communication fits into the 2nd group, but has some properties of the 1st. Many aspects are related to fibre optics with the difference, that the media is air and not fibers. Therefore are the required devices similar to those used with fibers.
The advantages of such a system are the following:
_ No need for digging up the roads
_ No radio frequency licenses are required
_ Bandwidth is equal or superior to fibre systems and much better than RF
_ Doesn't cause interference with existing electromagnetic equipment because interference on narrow band point-to-point connections is rather unlikely.