Marco Schiano

DISCUS: an end-to-end solution for ubiquitous broadband optical access

Fiber to the premises has promised to increase the capacity in telecommunications access networks for well over 30 years. While it is widely recognized that optical-fiber-based access networks will be a necessity in the short to medium-term future, its large upfront cost and regulatory issues are pushing many operators to further postpone its deployment, while installing intermediate unambitious solutions such as fiber to the cabinet. Such high investment cost of both network access and core capacity upgrade often derives from poor planning strategies that do not consider the necessity to adequately modify the network architecture to fully exploit the cost benefit that a fiber-centric solution can bring. DISCUS is a European Framework 7 Integrated Project that, building on optical-centric solutions such as long-reach passive optical access and flat optical core, aims to deliver a cost-effective architecture for ubiquitous broadband services. DISCUS analyzes, designs, and demonstrates end-to-end architectures and technologies capable of saving cost and energy by reducing the number of electronic terminations in the network and sharing the deployment costs among a larger number of users compared to current fiber access systems. This article describes the network architecture and the supporting technologies behind DISCUS, giving an overview of the concepts and methodologies that will be used to deliver our end-to-end network solution.

Measurement of birefringence correlation length in long, single-mode fibers

Measurements of birefringence correlation length performed on long single-mode telecommunication fibers are reported. The proposed technique relies on the statistical properties of the backscattered-field polarization, which was measured by means of a polarization-sensitive optical time-domain reflectometer. Experimental results are reported that show good agreement with the underlying theory based on stochastic differential equations.

Effect of polarization dispersion on the performance of IM-DD communication systems

Polarization mode dispersion can influence long distance IM-DD systems especially when optical amplifiers are used to increase the unrepeated link length. The impact of this phenomenon is analyzed in this letter both theoretically and experimentally by means of a 2.5 Gb/s synchronous digital hierarchy (SDH) commercial system. Polarization dispersion has a nonnegligible impact on the system performance when the associated differential group delay is of the order of 100 ps.<<ETX>>

In-field comparison among polarization-mode-dispersion measurement techniques

We report polarization mode dispersion measurements on a 168 km long undersea optical cable, performed with two techniques. From experimental results, statistical behavior of polarization parameters and their time fluctuations have been extracted. An average differential group delay of about 13 ps shows that dispersion-shifted fibers can be affected by a polarization dispersion significantly larger than standard step-index fibers. The correlation length of the polarization-coupling perturbation in the tested fibers is not negligible with respect to the link length.

A λ switched photonic network for the new transport backbone of Telecom Italia

The new photonic backbone of Telecom Italia is described starting from the expected traffic requirements and enabling technologies. The network basic structure and functions are discussed together with preliminary dimensioning data.

DISCUS: End-to-end network design for ubiquitous high speed broadband services

Fibre-to-the-premises (FTTP) has been long sought as the ultimate solution to satisfy the demand for broadband access in the foreseeable future, and offer distance-independent data rate within access network reach. However, currently deployed FTTP networks have in most cases only replaced the transmission medium, without improving the overall architecture, resulting in deployments that are only cost efficient in densely populated areas (effectively increasing the digital divide). In addition, the large potential increase in access capacity cannot be matched by a similar increase in core capacity at competitive cost, effectively moving the bottleneck from access to core. DISCUS is a European Integrated Project that, building on optical-centric solutions such as Long-Reach Passive Optical access and flat optical core, aims to deliver a cost-effective architecture for ubiquitous broadband services. One of the key features of the project is the end-to-end approach, which promises to deliver a complete network design and a conclusive analysis of its economic viability.

Polarization mode dispersion in long single-mode-fiber links: A review

Abstract Polarization mode dispersion (PMD) is the interplay of birefringence (both systematic and random) and coupling between orthogonal polarizations, in a single-mode fiber. PMD will set the ultimate limit to the fiber length × capacity product, when all the deterministic causes of dispersion are under control. We review the state of the art in this field, with emphasis on experiments, which demonstrate that the behavior of long links can be predicted with full confidence, in a statistical sense, from factory-based tests on individual cables. Successful application of the same experimental technique to detecting fiber stresses is also demonstrated.

Flexible node architectures for metro networks

This paper analyzes the optical transport requirements of future Metro nodes using the traffic forecasts available today. In a large metro network with 8 million users, flexgrid ROADM nodes can support the 2018 estimated traffic.

Flexible node architectures for metro networks [Invited]

This paper analyzes the optical transport requirements of future metro nodes using the traffic forecasts available today. Architectures and dimensioning of optical metro nodes are proposed to cope with 2018 estimated traffic in a large metro network with 4 million users. The challenge of providing dynamic transport services in a distributed data center scenario is also discussed.

Programmable multi-granular optical networks: requirements and architecture

This paper presents a programmable multi-granular optical cross connect (MG-OXC) and network architecture deployable in multi-service and multi-provider networks. The concept of programmable MG-OXC is introduced to provide a way of utilizing multiple switching/transport granularities to efficiently support the emerging traffic demands in both core and metro networks. For this reason, the supported bandwidth granularities include full lambdas, sub- and super-lambdas and multiple transport formats such as bursts, flows and packets. The programmability is envisaged by a software/hardware platform that simplifies network control, re-planning at the logical level and end-to-end service transparency, by translating the technology-specific information to technology independent services in an abstracted and logical manner.