The Modified Star–Ring Architecture for High-Capacity Subcarrier Multiplexed Passive Optical Networks

A modified star–ring architecture (MSRA) consisting of a star network on the upper level and many concatenated ring subnets on the lower level is proposed for subcarrier multiplexed passive optical network (SCM-PON). The upper level star network ensures high network capacity and its weakness in reliability is overcome by the concatenated ring subnets with self-healing capabilities. The self-healing function can be performed at remote nodes (RNs) by using optical switches (OS) to reconfigure the ring subnets if any link fails. Moreover, we design the cascade add/drop transceiver (CAT) structure in the lower level ring subnets to completely eliminate the optical beat interference (OBI) problem and achieve an OBI-free optical network. Finally, we set up an experimental network to demonstrate the feasibility of this cost-effective survivable structure.