Investigation of RS-Code DP-QPSK enabled FSO Communication Link under various Atmospheric Conditions

Modern free-space optics (FSO) communication have considered as solution for the scenarios like quick connectivity between two remote terrestrial links, radio wave pollution prohibited areas (for e.g. hospitals and industrial facilities). However, the reliability of the link are severely affected due to adverse atmospheric conditions due to turbulence and scattering media. This article presents the 112 Gbps data links using single channel dual-polarized (DP) quadrature phase shift keying (QPSK) modulation using Reed-Solomon (RS) codes as error correcting codes for improving the reliability of FSO communication links under fog affected atmospheric conditions. The coherent detection with digital signal processing (DSP) is considered for the demodulation of above optical received signal. Bit error rate (BER), received signal power, error vector magnitude (EVM), and coding gain were used to assess the system’s performance. Based on the result outcomes, on comparing the link performance under moderate fog conditions $\approx$3dB coding gain with $\approx$0.1 km link improvement achieved for the target log(BER) of −3.