Bit Error Rate Analysis of Free Space Optical Link Using Different Optical Windows

In this paper, we propose a model of free space optical communication system. The results of this paper show the BER of the system at different distances under high speed data rate of 1.25 Gbps. The different wavelength (window) used to calculate the performances at clean air turbulences of 6.5dB/Km. For focused laser beams propagating along the horizontal path we are using VCSEL. The avalanche photodiode (APD) is chosen for optical power detection, and the APD model is adopted for system evaluation. The NRZ-on-off keying (OOK) method is used for laser beam modulation.The average Bit-Error-Rate (BER) Vs distances and Q² Vs Distances curves of the FSO communication system are obtained.