Performance Analysis of a DPSK-based High-Speed Spectral-Efficient FSO System under Different Weather Conditions

摘要

The Free-Space Optical (FSO) communication system has proven its capability to enhance spectral efficiency andsupport high data rates owing to its large available bandwidth compared to other communication techniques. However, theFSO-transmission link is highly sensitive to dynamic conditions such as atmospheric turbulence and weather conditions,therefore, channel attenuation arises and the received optical signal is degraded and distorted at the receiver end. In thispaper, Dense Wavelength Division Multiplexing (DWDM) based (40 10) Gb/s FSO system performance is demonstratedover a maximum transmission link of 50–70 km with quality factor of Q = 16-4 in clear sky, condition whereas it is 0.1 kmto 4 km in fog to rain weather conditions for the BER range of 10 to 10 . The novelty in this work is to achieve theoptimum link distance with acceptable BER using a spectrally efficient (DWDM channel spacing of 0.6 nm), high speedadvanced NRZ-DPSK (10 Gb/s) modulation format under very dense fog and rain weather conditions. Furthermore, anEDFA pre-amplifier with a gain of 20 dB has been incorporated at the transmitter side to mitigate the impact of atmosphericattenuation to achieve maximum transmission range of 70 km in clear sky conditions.