Impact study of turbulence-induced scintillation on FSO link design

Free space optical (FSO) communication system remains a solution to the limitations of radio frequency (RF) spectrum and high data rate required for future applications. FSO is a promising technology for higher link capacity of non-detectable links to multi-gigabit per second. However, a beam of light propagating through the atmosphere has its phase, amplitude, and propagation direction fluctuating along the channel, as a result of scintillation loss which is a function of atmospheric turbulence. The randomness of air refractive index caused by turbulent channel changes with the local temperature, pressure, and humidity. This is usually quantified by refractive index structure constant (C
_n
²
) thereby affects the coherence of FSO links. In this paper, specific scintillation loss was estimated based on measurements over a channel. An FSO link with 100Gbps data rate was designed and simulated in an optisystem environment. Impact evaluation of the estimated turbulence-induced scintillation using BER (bit error rate) analysis on the FSO link was performed and an optical receiver was consequently designed for quality signal integrity.