High-Reliable WDM Optical Access Network Expanding by Double-Fiber-Tangent Ring

A WDM optical access network architecture based on double-fiber-tangent rings is proposed. With the proposed architecture, both data convergence and link protection can be realized. OLT and RNs can automatically switch to protection mode to overcome fiber failure occurring no matter in both primary ring (PR) and sub-ring (SR). The RNs designed as tangent points can realize wavelengths adding and dropping between PR and SR, and they also can realize network expansion through adding more wavelengths. In addition to this, the design of double-fiber ring can better the survivability and self-healing ability of the network.