Metro/access converged all-photonics networks with remote control and management technologies accommodating various types of terminals [Invited]

Extending dense-wavelength-division-multiplexing (DWDM) metro networks to access areas enables network operators to provide flexibly and reconfigurably end-to-end optical paths across access and metro areas to support emerging use cases with stringent bandwidth and latency requirements. This evolution in optical network architecture will also contribute to addressing social issues related to the global warming crisis by reducing the power consumption of optical/electrical conversion and electrical processing at access/metro boundaries. Active efforts have been made to actualize all-photonics metro/access converged networks (APNs) based on this architecture evolution mainly from the perspective of end-to-end main-signal transmission in the physical layer. This paper discusses the need for studies from a different perspective. To extend APN coverage to access areas outside network operator buildings, technological innovation in optical path control and management is essential especially from the perspective of remote terminal control and management. We overview three main technical challenges: establishing a remote-control channel, managing ports on the access side, and blocking rogue remote terminals. The last technical challenge is raised for the first time in this paper, and an approach for addressing it is proposed. We comprehensively confirm the feasibility of each approach to the three technical challenges through experimental demonstrations using prototypes of an APN access node, defined as a Photonic Gateway (GW), and the APN controller. The Photonic GW prototype employs a 10-gigabit-capable symmetric passive optical network for in-channel control of remote terminals, regardless of the type, and addresses the first technical challenge. The APN controller implements a sequence for the initial terminal-connection method to address the second technical challenge, and a sequence for optical-path setup including a proposed method for detecting and blocking incorrect light to address the third technical challenge. When new 100-Gb/s C-band DWDM digital coherent remote terminals are connected to the Photonic GWs, the period for the APN controller to execute the set of sequences is only 18 s, which is sufficiently short for the process before optical-path establishment. Only when the optical power and emission wavelength of new remote terminals are verified to be correct, an end-to-end optical path passing through two Photonic GW prototypes is established autonomously based on the access-side connectivity between the remote terminal and Photonic GW, which is identified during the initial terminal-connection procedure.