Low-Cost All-Optical Switching Nodes for Ultra-Dense Optical Metro-Access Networks.

Optical metro-access networks (OMANs) must enable the connectivity among 5G-based radio stations, edge datacentres, businesses, and home users. In such a heterogenous scenario, greater scalability, higher levels of dynamic connectivity and flexibility, reduced end-to-end latency, and increased energy efficiency are required. Mesh-based ultra-dense wavelength division multiplexing (u-DWDM) OMANs using reconfigurable optical switching nodes are a promising solution. However, the designs of traditional optical switching nodes relay on wavelength-selective switches (WSSs), which provide high network reconfigurability only at a high cost, making them prohibitive for OMANs. Moving away from this design approach, we proposed a novel low-cost and energy-efficient design based on a modular DWDM structure for reconfigurable optical add-drop multiplexer (ROADM) and optical cross-connects (OXC) nodes compatible with mesh-based u-DWDM OMANs. Results show that proposed solutions can provide performance close to that of WSS-based OXCs but with a switching node cost reduction of one order magnitude.