In the last decade we assisted to a continuous growth of the metro network (MAN), now facing a bottleneck in the transmission and routing of the huge amount of data due to the increase of the number of users, the content size, and to the convergence with mobile and datacom networks. Photonics is a key enabling technology for the evolution of the entire telecommunications infrastructure, supporting increasing bandwidth requirements and quality of service.
The aim of PASSION is to develop new photonic technologies and devices supporting sustainable MANs, enabling multi-Tb/s capacities over a few hundred-kms distances. The new MAN offers: (i) reduced costs, energy consumption and equipment footprint, that are achieved by the development of compact/cost-effective switching technologies and transmitter (using directly modulated vertical-cavity surface-emitting lasers, VCSELs) and multi-channel coherent receiver modules; (ii) increased flexibility and modularity using sliceable bandwidth/bitrate variable transceivers (S-BVTs); (iii) increased network and system scalability, programmability and reconfigurability, enabled by agile aggregation in the spectrum, polarisation and space dimensions and the implementation of a software defined networking (SDN) control platform.
Fig.1 shows the S-BVT Tx based on the modular approach: the module integrating 40 VCSELs in Silicon photonics (SiPh) and enabling up to 2 Tb/s aggregated capacity is the building block of the S-BVT. By combining four modules, a full 160-channel Tx supermodule is obtained with 25-GHz granularity over the whole C band and with up to 8Tb/s capacity. By exploiting also polarisation-division multiplexing and spatial multiplexing with bundles of fibres or multi-core fibres, PASSION Tx is able to reach a capacity per link higher than 100 Tb/s. PASSION network platform includes an innovative energy-efficient and small-footprint node approach, adopting flex-grid aggregation/disaggregation/add switches, high-connectivity multicast switches (MCS), and large-port photonic polymer PLC-based space switch matrixes. Such a S-BVT based network architecture (Fig.2) guarantees reconfigurability, flexibility and scalability to support a “pay-as-you-grow” scheme. SDN ensures network programmability, fitting network operator requirements and roadmaps.