Open Space Laser Communication Link Analysis, Multi-path Effects

Free space optical communication became a new direction of optical communication because of its advantages of high bit rate, high security, broad bandwidth and good performance on anti-jamming. Based on the developed actuality of FSO technology, this paper discussed the key technique of FSO. In these key technologies, this paper laied emphasis upon influence resulted from optical channel.Particles in atmosphere scatter laser and absorb the energy of laser, these causes attenuation of laser. One of the reasons of attenuation is absorbing of particles. A quantum measuring efficiency of extinction and a function of scattering both are important in theory of scattering. Besides scattering can causes multipath effect. Then this paper discusses particularity of multipath effect of laser.This paper mainly discussed multipath delay effect caused by atmosphere particles scatter. Atmosphere particles mostly include cloudy liquid aerosol in atmosphere. Reasoning more than one multipath delay formulas simulate them repeated calculation contrast the numerical value, gained two modified mathematic models which are more approach the experiment result. The two models are respectively laser transmit through cloud and multipath scatter medium. Then analyzed the modified models and investigated influences of quanta to multipath delay further.Based on the analysis of multipath delay, combine the experiment experience of foreign research with domestic practical circs, this paper brings up assumption of experiment. The assumption mainly includes equipments of experiment conditions some problems encountered maybe in the experiment and solving methods.This paper is useful for reference to laser multipath effect.