High Speed Long-Haul Hybrid MDM/FSO System under Diverse Turbulent Conditions

A high speed $6 \times 20$ Gbps hybrid free space optics and mode division multiplexing (FSO-MDM) system considering weak-to-strong turbulent as well as diverse climate conditions is proposed. Three laguerre-gaussian (LG) modes viz. 00, 01 and 02 are incorporated for six transmission signals. The results indicate that faithful FSO range of 17-50km is obtained under weak-to-strong turbulent condition. Maximum signal to noise ratio of 50 dB can be obtained for the proposed work for LGOO followed by LGOI and LG02 mode signals. It is also shown that Gamma-Gamma FSO fading model performs better for the proposed model than log-normal under different climate conditions. The obtained optical spectra, eye pattern as well as timing diagrams clearly indicate the optimum performance of the system. Moreover, the existing model indicates better performance than existing models for long-haul applications. Therefore, a high speed FSO-MDM system at 120Gbps data rate over 50km range is successfully designed and realized.