Photonic gateway architecture extension and guard time-free initial connection method with point-to-multipoint remote control for metro/access converged all-photonics network

Abstract

Emerging use cases with demanding bandwidth and latency requirements, as well as the challenge of reducing power consumption, are driving the need for evolution in optical network architectures. An all-photonics metro-access converged network (APN) aims to actualize a flat architecture by expanding dense wavelength-division-multiplexing (DWDM) metro networks into access areas. The APN flexibly and dynamically provides optical connectivity between any two points, even across the boundaries between access and metro areas according to individual application requirements and traffic-load status. To actualize and further evolve the APN concept, several technical challenges regarding access nodes, defined as Photonic Gateways (GWs), still remain. From an access node functionality perspective, first, the Photonic GW should forward various types of optical paths. Unlike reconfigurable optical add/drop multiplexers in current metro networks, which are specifically designed to cross-connect DWDM signals, the Photonic GW needs to handle various lights and optical signals, including short-reach applications and emerging non-communication use cases. Second, the Photonic GW should provide remote control channels to user terminals (UTs) in a more scalable and cost-effective manner within the node-footprint and power-consumption constraints. Remote and in-channel UT control is required to place flexibly the endpoints of a wavelength path, i.e., UT, beyond the control-plane network. Then, from the controller perspective, the physical connectivity between the newly connected UT and the access-side port of the Photonic GW should be autonomously identified for plug-and-play operation. Since UTs are widely distributed within an access area, there is a need for an initial connection method that does not require timing adjustments to connect to the APN between newly connected UTs. This paper presents an extension to the APN architecture that allows the Photonic GW to increase the types of accommodable optical paths and to enhance the scale of remote UT control. This paper also proposes an advanced initial connection method that works even when multiple UTs are simultaneously connected to the APN. The extension to the APN architecture and the initial connection method are verified through experiments based on a Photonic GW prototype that fully complies with the extended APN architecture and comprises four functionally disaggregated units, 100-Gb/s C-band DWDM digital coherent UTs, and 25-Gb/s O-band non-DWDM intensity modulation and direct detection UTs. A 10-gigabit-capable symmetric passive optical network is adopted for remote UT control. The proposed initial connection method eliminates the connection interval of 6 s or more between newly connected UTs and achieves guard time-free operation.