Experimental investigation on the fundamental physical-layer capabilities for converged metro–access architectures using coherent transceivers

We present a fully experimental investigation on the fundamental physical-layer capabilities of future converged metro + access architectures using commercial coherent transceivers and reconfigurable optical add-drop multiplexers (ROADMs), which are placed at the boundary between the two network segments to implement all-optical routing of upstream and downstream wavelengths. For the access part, we focus on passive optical network architectures, as they are the most commonly deployed and also the most demanding at the physical layer due to their very high loss and single fiber operation. In our experimental demonstration, we target very high bit rates (200G and 400G net data rates) and key physical-layer scalability, such as the maximum achievable optical distribution network loss as a function of available optical signal-to-noise ratio in the metro segments, ROADM internal insertion loss, and other possible impairments, like tight optical filtering or power level unbalances.