Communication of Free space optics system functions as fixed Free Space Optical systems in other words the traditional. The technology is situated on the connection among Free Space Optics wireless units; each consists of an optical transceiver with a transmitter and a receiver to provide full-duplex capability (bi-directional). There is a fiber at the receiver side which turns the electrical signal to the optical signal in this end. A laser driver amplifies this electrical signal and provides enough current to drive the laser diode. Controlled light from the laser is heading for the receiver which focused their ray onto a silicon Avalanche photo Diode (APD). This APD changes the optical signal to an electrical one. After re-forming and some din filtering the electrical signal is turned back to the Optical signal. The maximum amount of data can be transferred at the speed of 2.5 Gbps. An optical aerial used to emit the ray using Single Mode Fiber (SMF) termination to free space .At the receiver the optical beam is focused onto the fiber for detection. And amplify the beam signal if the climate is not good and this will be done by the Erbium Doped Feedback Amplifier (EDFA). Since fiber and free space optical broadcast links hold the same optical signal is capable of utilizing developed technologies and optical components developed for high bit rate fiber transmission. A free space broadcast is equal to the SMF broadcast assuming we omit atmospheric turbulence factor.
Scientists are proposing that between orbiting satellites we should add FSO systems and combine with a single mode fiber (SMF). When an optical ray is broadcasted the atmosphere requires a large aperture lens for the camera because of the large diameter at the receiver. The optical signal that is focused onto the fiber using the lens will be affected by turbulence as it goes through the atmosphere and vibrations at the installation site. The disadvantage of the atmospheric turbulence will bring about the reductions changes in the Angle of arrival (AOA) and in turn will lead to important variations in the power of light concentrated on the Single Mode Fiber.