On the performance of FSO communication system with WDM and MIMO structure under different turbulent atmospheric conditions

Abstract Free space optical (FSO) communication link is highly weather dependent as the signal passes through the atmospheric channel. The main impairment is atmospheric turbulence, which introduces fading and breakdown the system performance. The performance of FSO link is evaluated in terms of attenuation and link length under different weather conditions. Taking a step further toward the improvement of FSO communication system, wavelength division multiplexing (WDM) is widely used in optical fiber in order to exploit the capacity of a fiber channel more efficiently. Additionally, multiple input multiple output (MIMO) mechanism represents one of the atmospheric mitigation techniques. Thus, integration of MIMO and WDM will provide astonishing results in FSO communication systems. This paper particularly focuses on analyzing the performance of FSO single input single output (FSO-SISO), FSO-WDM, FSO-MIMO, and FSO-WDM-MIMO systems considering different weather conditions. Performance of the different systems has also been compared in terms of received signal power, the quality factor, the bit error rate, and the maximum separation between the transmitter and the receiver for a given received signal level and for various atmospheric conditions. Our results show that increasing the transmitted power and receiver aperture diameter will improve the performance of the system under heavy fog and dense fog.