Transmission of 128 Gb/s Optical QPSK Signal over FSO Channel under Different Weather Conditions and Pointing Errors

Abstract

Free space optics (FSO) is a promising technology for high data rate transmission where data is transmitted wirelessly from one place to another. It has a variety of applications nowadays including indoor, outdoor, underwater, and deep space communications. However, the availability of link under various atmospheric conditions is a major concern. In this study, we evaluate the transmission of 128 Gb/s optical quadrature phase shift keying (QPSK) signal under different weather conditions and pointing errors. Simulation parameters such as FSO link range, atmospheric attenuation, pointing loss, and wavelength are taken into consideration. The system performance evaluation parameters including eye diagram, constellation, and received signal to noise ratio (SNR) are compared to find the best performance under different weather conditions. Numerical simulations show that the pointing errors up to 10 μrad and bad weather conditions up to 15 dB attenuation has sever effects on the system performance and we should use digital signal processing and equalization to enhance it.