A novel tangent-ring TWDM metro-access optical network featuring reconfiguration and reliability

In this paper, we propose a novel tangent-ring TWDM metro-access network providing flexible reconfiguration and high reliability. With the innovate design of flexible distribution node (FDN) and distributed control mechanism (DCM), three kinds of reconfigurable TWDM-PONs can be built to achieve efficient intra and inter ONU direct communication by reusing optical distribution network (ODN). In addition, three-level protections covering both feeder and distribution fibers are also separately supported by the use of optical switches and natural advantage of single-fiber tangent ring topology. Moreover, with the use of simplified RN* and ONU*, the proposed network can upgrade smoothly and achieve pay-as-you grow. The network capacity, OSNR, cost and transmission performances are also studied, which suggests that this network has a good performance.