Free atmospheric broadcasting of radio, TV and teletext with laser radiation

The point to point telecommunication in the atmosphere with laser signals using the existing optoelectronic technology is an option of the modern communications design. An optical link is strong depending on the optoelectronic hardware parameters and to the topology or to the environment of the applications area. Many laser-links are already fabricated for use in military or in commercial applications. Main advantages are the freedom from licenses, the RFI-EMI immunity, the wide bandwidth and the information security. Main disadvantages are the atmospheric steady and variable attenuation, the radiation hazards and in some cases the material cost. Based on this know-how we describe in this paper the more important broadcasting parameters of radio- TV-teletext programs with laser beams, starting from the atmospheric transmission influence, continuing with a laser selection guide and with some broadcasting electronic techniques and ending with the proposed modification of a coherent laser-link to a new active receiver system which fulfill normal or special laser broadcasting options. Possible applications of our study may be the point to multi-point optical communications for local pay TV, the allocation of optical bands for broadcasting, the radii of cellular laser broadcasting, the simulcasting with laser and RF carriers, the implementations of an interactive Radio and TV, etc.