Experimental assessments of a coherent DSCM and SOA-based WDM metro-access network architecture with enhanced flexibility and capacity.

Metro-access networks are a type of optical network connecting metro hubs with various subnetworks, covering from rural to dense urban regions. In the long term, the metro-access network is expected to address hundreds of Tb/s aggregated traffic, which makes spectral efficient multiplexing techniques a must-have. Combining wavelength division multiplexing (WDM) and digital subcarrier multiplexing (DSCM) techniques is a possible successful industrial approach to cope with this challenge. However, the ever-growing demand for bandwidth/wavelength inevitably induces increased complexity and cost of the metro-access network architecture. In this Letter, we describe the design and experimental assessment of a semiconductor optical amplifier (SOA)-based optical add-drop multiplexer (OADM) with the coherent DSCM technique, which can dynamically add and drop traffic at any node within the network and enable lossless transmission at a relatively low cost due to photonic integration. The results show that the proposed architecture can support up to five nodes at a net data rate of 291 Gb/s/λ with negligible penalty from dropping and adding operations, indicating its great potential for long-term metro-access network adoption.