Ring-Based Hybrid GPON Network with Inter-oNU Transmission Capability

This paper proposes the Hybrid Optical Fiber (OF)-Free Space Optics (FSO) based Inter-Optical Network Unit (ONU) transmission capable Wavelength Division Multiplexing (WDM)-Passive Optical Network (PON) architecture. This architecture can transmit up to 40 Gbps for downstream, upstream, and inter-ONU transmission. The downstream transmission is flowing from the center office (CO) to respective ONUs while Inter-ONU transmission is performed from one ONU to another ONU which are connected in a ring manner. The upstream transmission is performed from a particular ONU and travels towards the CO via a circular ring. The upstream signal can be transmitted on the same wavelengths which are used for the downstream transmission and therefore it utilizes the available bandwidth efficiently. In the proposed architecture, four 10 Gbps optical line terminals (OLT) transmit the signal through 20 km of single-mode fiber (SMF). Inter-ONU feature increases the reliability and survivability of the optical network. The bit error rate (BER) performance of the proposed architecture for the main and Inter-ONU transmission is reasonably good for the combination of 20 km feeder fiber (FF) and 200 m distributed fiber (DF)/FSO link. The architecture also provides better receiver sensitivity for a hybrid OF-FSO optical network with Inter-ONU transmission.