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The hybrid system WDM Radiofrequency over free space optics\fiber optic (RoFSO\FO) is one of the modern technologies that support developing the 5th generation for the communication network. The WDM RoFSO\FO system is designed to transmit high data rates over a long distance under variable weather conditions (fog, dust, and rain). Where the attenuation caused by atmospheric changes is one of the most important obstacles faced the FSO channel. The spatial diversity technique is used by sending multiple copies across the free space to improve system performance. The hybrid design tested the performance of 16 channels optical transmission, each channel transmits 2.5Gbps data rate modulated by PSK modulator on a 20GHz radio frequency signal. Where 40 gigabits per second was transmitted via 4000m multi-channels FSO extending to 120 km optical fiber as a total distance, 80 km of which was amplified by Raman / EDFA hybrid optical amplifier. The bit error rate BER and the Q-factor monitored and compared with the standard Kim model. From the results obtained by using the OptiSystem simulation, an improvement in the system was found significantly by increasing the transmission capacity when using WDM technology and long-distance transmission under variable weather conditions without adding a light source.

In this paper, a hybrid system is proposed consisting of a radio-frequency (RF) over free space optic/fiber optic (RFOFSO/FO). A free-space communication system is an alternative to optical fibers if it fails in performance or if it is difficult to propagate. This hybrid system is an effective solution for developing new generation networks, by transmitting the optical signal over long distances within the C-band, and L-band. The proposed system sends the radio frequency signal through the optical free-space link then extends to 80 km of optical fiber, of which 40 km is amplified by the Raman/EDFA hybrid optical amplifier. This paper aims to test the performance of the free space optic link under different weather conditions. The atmospheric attenuation, which reduces visibility, was considered as the main challenge. Several copies were sent in different paths in FSO to meet this challenge. The submitted system was implemented in the case of transmission in a wavelength within the C-band and also in L-band. The results of the hybrid system were compared by measuring the bit error rate (BER) and Q-factor under dust and fog conditions relative to Kim’s standard model by using Optisystem. The results obtained showed an effective sensation at a long haul, inn addition to not using an additional light source when transmitting for such long distances.