Performance Improvement of Hybrid FSO/Fiber Optic Communication System under Different Modulation Schemes

Optical wireless is used when the FSO system implementation fails due to turbulent weather conditions that deteriorate and thus will degrade signal strength in transmission. To overcome these issues, a multi-channel FSO transmitter and dispersion-compensating fiber (DCF) were used in the optical link with high transmit power. In this work, a hybrid FSO/Fiber Optic (FSO/FO) is proposed to explore the best modulation type under different climatic conditions, in which the hybrid correlation bit error rate (BER) and quality factor (Q-factor) are investigated. Erbium-doped fiber is adopted and a multi-channel transmitter is used with different states of single and dual channels with the same input power. It is observed that the dual channel shows better Q-factor results than the single channel. The proposed system achieves better results in 10 Gb/s rain conditions for optical fibers with a length of 40 km for the inspection range from 1000m to 12000m when the input power is 160 mW. The proposed system achieved a Q factor equal to 5.7 when the DPSK modulation is at a transmission distance of 12000 m for the fiber link and a Q factor equal to 6.7 when the DPSK modulation is after 12000 meters for the FSO.