Bit error rate reduction of optical communication by means of Tip/Tilt correction

One of the parameters for evaluating the free space optical link is BER. The atmospheric turbulence increases BER of telecommunication link. One of the BER reduction methods is the use of correction of dynamic aberrations caused by atmospheric turbulence. In this paper first, by using phase plates, atmospheric turbulence has been simulated. In order to determine the refractive index structure parameter, fluctuation of angle of arrival and fitting curve into probability density function of scintillation beam have been applied. The obtained value of Cn2, from two methods is of order of 10−14m−2∕3, which are in good agreement with each other. In the following, BER of free space telecommunication link before and after correction has been measured using the correction of tip and tilt low order aberration in the presence of simulated turbulence at laboratory. In this paper, by indirect method, BER was measured by probability density function of fluctuation beam. Before correction, the value of BER was 3.302×10−4 that which reduced to 4.276×10−7 after the correction.