An Convergent WDM-PON Architecture Based on Dual-fiber Tangent Rings Featuring Protection and Extension

A novel wavelength-division-multiplexed passive optical network (WDM-PON) architecture based on dual-fiber multiple tangent rings is proposed. One primary-ring (PR) and certain sub-rings (SRs) are controlled by one optical line terminal (OLT). The design of tangent remote nodes (RNs) guarantees the transmission and convergence of signals between PR and SRs. This network effectively overcomes single-fiber or dual-fiber faults. Signals can be switched between dual fibers by optical route switch (ORS). Simultaneously, the usage of different fibers can reduce the crosstalk in the upstream signals and downstream signals. Tangent RNs help to expand the network, which is highly significant for large-scale optical access network in next generation.