This paper introduces a novel concept for Remote Radio Head (RRH) powering: PoF pooling, and its application for Multi-Core Fiber (MCF) enabled by SDN. Simulations using stochastic geometry prove the benefits of this approach in a phantom cell scenario. PoF pooling concept As the power requirements of small-cell RHH of next generation cellular systems become lighter thanks to technologies like Radio-over-Fiber (RoF), the prospects to make possible cellular networks remotely fed by optical fiber are becoming a reality. One of the challenges for PoFsupported 5G systems is to make them scalable to hundreds or thousands of small cells by using a single power supply location, either at the Central Office (CO) or the closest Macro-cell Base Station (MBS). Even though local power units on each base station are no longer needed, achieving high savings, the amount of costly HPLDs (High-Power Laser Diodes) required to feed all the cells may hamper many initiatives until PoF becomes mainstream. Furthermore, a static allocation of fibers for remote powering may hinder flexible resource allocation in the access network. In this paper we present the concept of PoF pooling and PoF switching to address this problem, allowing a selective use of a fiber core for power, data transfer or both. The concept of PoF pooling is sketched in Fig. 1. The infrastructure is composed of multiple cell sites connected to a CO through a hy-ODN Cell site (CS) A

Innovative photonic solutions designed and developed in the H2020 research project PASSION are presented for the future metropolitan area network (MAN) supporting different aggregated data traffic volumes and operating at heterogenous granularities. System performance evaluated both by simulations and experimentation regarding the proposed vertical cavity surface emitting laser (VCSEL) -based modular sliceable bandwidth/bitrate variable transceiver (S-BVT) are shown in realistic MANs organized by hierarchical levels with the crossing of multiple nodes characterized by new switching/aggregation technologies. The capabilities and challenges of the proposed cost-effective, energy-efficient and reduced footprint technological solutions will be demonstrated to face the request of huge throughput and traffic scalability.

Upcoming metro networks are required to transport huge and highly dynamic data traffic whilst resulting cost and power efficient. Thus, novel metro network architectures are being investigated to increase the transport capacity (e.g., leveraging dense photonic integrated technologies), and provide effective SDN-based network programmability. The EU-H2020 PASSION project targets such a metro network design exploiting: i) programmable, modular, cost-efficient and low-power sliceable bandwidth variable transceivers (S-BVTs) formed by a pool of vertical cavity surface emitting lasers (VCSEL) and Coherent Receivers (CO-Rx); ii) hierarchical switching nodes in a flexigrid network to attain all-optical transport and aggregation. The SDN-based control functions considers the features of the adopted PASSION transport layer. First, we detail the defined interfaces (APIs) for the automatic transport network programmability. Such (RESTful-based) interfaces are validated within the ADRENALINE testbed. Next, upon dynamic connection requests with heterogenous data rate demands, an on-line Routing and Spectrum Assignment (RSA) algorithm based on a modified K shortest path (K-SP) is proposed. To accommodate a connection request, a set of optical flows having their own S-BVT VCSEL and CO-Rx devices at the endpoints and path's frequency slots are selected and configured. Each optical flow is subject to the spectral continuity and contiguity constraints. The performance of the RSA algorithm for several traffic loads is experimentally evaluated through different figures of merit (e.g., blocked bandwidth ratio, average used of S-BVT devices, etc.) and diverse RSA's K-SP settings.

To deal with the challenging requirements of metropolitan area networks (MANs), it is essential to design costeffective systems that can support high capacity and dynamic adaptation, as well as a synergy of programmability and efficient photonic technologies. This becomes crucial for very large MANs that support 5G, where multi-hop connections will need to be dynamically established at target capacities beyond Tb/s. Programmability, automation and modularity of network elements are key desired features. In this work, a modular photonic system, programmable via a software defined networking (SDN) platform, designed for dynamic 5G-supportive MANs, is described and analyzed. We consider modular sliceable bandwidth/bitrate variable transceivers (S-BVTs) based on vertical-cavity surface-emitting laser (VCSEL) technology and dense photonic integration. The proposed system and its programmability are experimentally assessed using VCSEL with 10 GHz bandwidth. The experiments are performed over connections as long as six-hop and 160 km, from low-level aggregation nodes to metro-core nodes, thereby enabling IP off-loading. Furthermore, a numerical model is derived to estimate the performance when adopting higher bandwidth VCSELs (≥ 18 GHz) and integrated coherent receivers, as targeted in the proposed system. The analysis is performed for both 50 GHz and 25 GHz granularities. In the former case, 50 Gb/s capacity per flow can be supported over the targeted connections, for OSNR values above 26 dB. When the granularity is 25 GHz, the filter narrowing effect severely impacts the performance. Nevertheless, 1.2 Tb/s capacity (scalable to higher values if spectral/spatial dimensions are exploited) can be achieved when configuring the S-BVT to enable 40 VCSEL flows. This confirms that the system is promising to support Tb/s connections in future agile MANs.

An SDN-enabled modular photonic system architecture, including VCSEL-based bandwidth/bitrate variable transceivers, for multi-terabit capacity transmission and agile spectrum/space switching in optical metro networks is presented, providing the proposed technological solutions, programmability aspects and preliminary assessment.