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To meet the requirements of 5G high capacity optical metro networks, a programmable disaggregated multi-dimensional sliceable bandwidth/bitrate variable transceiver (S-BVT) is proposed. Specifically, transceiver multi-dimensionality is presented exploiting spatial, polarization, and spectral information as a solution to support network capacity and bandwidth scaling 5G requirements. Space division multiplexing is implemented by considering a 19-core multicore fiber enabling capacity scaling with the number of cores, whereas polarization division multiplexing is assessed enabling 50% spectral saving by considering two orthogonal polarization components. Finally, by the implementation of multi-band transmission systems, the optical bandwidth can be increased by a factor of 10, compared to a conventional C-band system. In these last two cases, the existing spectrum and network infrastructure can be reused, bringing new capabilities. In particular, in this work, multi-band transmission is assessed by exploiting the C-band and L-band. Additionally, disaggregation is also addressed at the transceiver level to enhance network flexibility, avoiding vendor lock-in while achieving efficiency and cost reduction. Disaggregation enables assembling open components, devices, and sub-systems into optical infrastructures and networks. On the other hand, the adoption of the software defined networking paradigm enables system/network programmability and reconfigurability, promoting an efficient use of the multi-dimensional network resources. Therefore, in this work, we analyze and experimentally demonstrate different S-BVT advanced functionalities suitable to support the stringent network requirements of 5G. These capabilities include rate/distance adaptability, programmability/configurability, disaggregation, and multi-dimensionality. Different network scenarios have been considered to assess the S-BVT functionalities, enabling Tb/s optical transmission.

The metropolitan area network (MAN) segment is becoming one of the most challenging due to the ever increasing volume and dynamicity of traffic, induced by novel and bandwidthhungry services and applications as well as the need for instant data access in our globallynetworked and hyperconnected society. In addition to the ultra-high capacity and dynamic scenario, another challenge is related to the stringent requirements in terms of both capital and operational expenditures (CAPEX/OPEX).

We demonstrate two advanced services deployed in a novel SDN/NFV optical fronthaul network combining analog radio over fiber (ARoF) and power over fiber (PoF); vertical service management for virtual content delivery networks (vCDNs), and user mobility and remote optical power management for femto cells., Grant numbers : AURORAS - Autonomic and disaggregated optical networks leveraging edge computing and photonic technologies (RTI2018-099178-B-I00).

In this paper we analyze the perspective of digitized radio over fiber (DRoF) fronthaul, showing how to meet the requirements to cope with the future radio access networks (RANs). This entails the introduction of space division multiplexing (SDM) while increasing the flexibility and capacity of the DRoF transceivers.Since the evolution of the DRoF fronthaul is being revised and re-defined, in the blueSPACE project we propose two different DRoF transceiver options. The first option consists on simple transceiver, based on the recent standard specifications and, therefore, expected to be deployed in the short-term. The second options is a more advanced transceiver that features high flexibility, relying on a strong DSP and targeting a long-term deployment. Besides a basic characterization of both solutions, we also analyze additional aspects related to the design and implementation of these two DRoF solutions and their integration into an SDM based RAN. This includes the programmability and interaction with the control plane.

In this paper we propose a passive optical network based on hybrid wavelength/space division multiplexing for digitized fronthaul delivery, capable to meet the requirements of the future radio access networks. Besides explaining this specific network architecture, we also discuss the different programmable data plane elements. Additionally, we evaluate and demonstrate the support of an extended version of 5G-NR radio signals.

Long-wavelength vertical cavity surface emitting laser (VCSEL) technologies can represent an alternative solution for the development of transmitters with reduced cost, power consumption and footprint for very-high capacity metropolitan area systems. Exploiting direct modulation (DM) and advanced modulation formats, such as discrete multitone (DMT), and aggregating multiple DM-VCSELs emitting in the C-band with dense wavelength division multiplexers (WDM) in SOI chips allows to achieve multi-Tb/s transmitter module with 25 GHz granularity [1].

The combination of Spatial Division Multiplexing (SDM) with flexi-grid WDM enables optical transceivers to provide super-channels exploiting both spectral and spatial dimensions. In this paper we extend the SDM-WDM transceivers to support sliceability for the first time, and make an effective use of spatial and spectral resources. The proposed architecture provides multiple independent spectral-spatial super-channels (i.e., slices) sharing the same transceiver and exploiting different spectrum/core/ mode resources. The proposed architecture also enables to monitor the BER of the provisioned slices in order to detect any signal quality degradation due to the provisioning of additional slices. On the other hand, there is a general trend towards the disaggregation of the optical networks. In this paper we also propose the first open API based on YANG data model and NETCONF protocol for SDN-enabled sliceable SDM-WDM transceivers. The proposed transceiver is experimentally validated in a joint testbed between CTTC and KDDI research., Grant numbers : TEC2015-69256-R project. https://doi.org/10.1364/JOCN.11.00A123

This paper presents optical (SDM/WDM) and packet transport solutions for 5G fronthaul/backhaul and the hierarchical Transport SDN control and monitoring architecture. It dynamically provides multiple spectral-spatial super-channels and packet flows, and monitors the signal quality degradation of the optical super-channels and the aggregated packet traffic.

In this paper, vertical cavity surface emitting laser (VCSEL) technology is presented as potential prominent performer to address key challenges and novel functionalities of future optical metro networks. The adoption of VCSEL-based modules is particularly attractive for the implementation of programmable (SDN-enabled) transceiver architectures, targeting a radical reduction of cost, power consumption and footprint. Different flavours of these architectures are presented to enable agile, scalable and high capacity optical metro networks. Furthermore, advanced functionalities and programmability aspects are analysed to explore the potential of adopting solutions based on this technology.

We experimentally demonstrate transparent and dynamic delivery of mobile front-/back-haul in converged optical metro architecture, employing software-defined networking enabled sliceable bandwidth variable transceivers based on adaptive multicarrier modulation. The proposed architecture is specifically tailored for a transparent services delivery across the access and metro network segments. Therefore, several challenges are discussed, such as functional split requirements and bidirectional transmission (duplex) over these different segments. In order to prove the validity of this concept, network experiments have been carried out in a hybrid metro/access testbed. Results show successful connectivity at distances up to 175 km, including the access segment, and capacities beyond 20 Gb/s per flow.

The Centralized Radio Access Network (C-RAN) architecture is necessary to achieve the target goals that have been set for 5G. However, as the number of radio signals to be transported between the Centralized Base Station (CBS) and the Remote Antenna Units (RAUs) grows large, the utilization of contemporary fronthaul technologies (such as CPRI) becomes more difficult. The reason for this is that these Digital Radio-over- Fibre (RoF) solutions were originally designed to be transparent to the transported radio signal, introducing a negligible distortion at the cost of expanding the bandwidth notably and increasing the processing delay. As the assumption of an ideal fronthaul will not be realistic any more for future C-RANs, a novel design paradigm is needed in which the impairments introduced by both fibre fronthaul and wireless air-interface are jointly taken into account. In this contribution, we present our vision about the advantages of using an all-analog fronthaul, identifying potential challenges and proposing possible solutions to address each of them. We claim that the use of low-cost analog components in the RAUs will not only reduce the End-to-End (E2E) latency of the mobile network, but will also enable an ultra-dense deployment of small cells taking advantage of the Passive Optical Network (PON) infrastructure that is already available today in most urban centres., Grant numbers : This work has received funding from the Spanish Government under Project TEC2014-59255-C3-1-R (ELISA) and the Catalan Government under Grant 2014SGR1567.

We propose a programmable 400-G discrete multi-tone (DMT) transceiver with policy-based control. We experimentally demonstrate the 400-G DMT transceiver enabling either capacity, distance, or energy efficiency priority in a four-node photonic mesh network.

This article reports the work on next generation transponders for optical networks carried out within the last few years. A general architecture supporting super-channels (i.e., optical connections composed of several adjacent subcarriers) and sliceability (i.e., subcarriers grouped in a number of independent super-channels with different destinations) is presented. Several transponder implementations supporting different transmission techniques are considered, highlighting advantages, economics, and complexity. Discussions include electronics, optical components, integration, and programmability. Application use cases are reported.

We numerically analyze a flexgrid metro network scenario identifying the requirements for BRAS centralization. A cost-effective S-BVT architecture based on MB-OFDM and DD with DSP-enabled software-defined flexible/adaptive capabilities is proposed and experimentally evaluated for supporting multiple 10Gb/s connections.

In this paper, bandwidth and bit rate variable optical transceiver architectures, targeting high capacity and low cost, are presented and discussed as technology enablers for inter-data center connection, in the context of flexgrid networks. Potential candidates, based on multicarrier technologies, are considered for their spectral efficiency and reconfiguration capabilities. Cost-effective designs using low complex digital signal processing are proposed for flexible, software-defined transmission. Furthermore, programmable, modular transceiver architectures, equipped with tuneable optoelectronic front-end, are investigated for enabling sliceable functionality.