Émile Archambault

Design and Simulation of Filterless Optical Networks: Problem Definition and Performance Evaluation

Filterless optical networks based on advanced transmission technologies and passive optical interconnections between nodes offer a lower-cost alternative to optical networks based on active photonic switching. A design and simulation platform is proposed for studying these novel network architectures and looking at their performance characteristics. Simulation results are presented for three reference network topologies, along with a comparative cost and performance study of active photonic and passive filterless optical network solutions.

Routing and Spectrum Assignment in Elastic Filterless Optical Networks

Elastic optical networking is considered a promising candidate to improve the spectral efficiency of optical networks. One of the most important planning challenges of elastic optical networks is the NP-hard routing and spectrum assignment (RSA) problem. In this paper, we investigate offline RSA in elastic filterless optical networks, which use a passive broadcast-and-select architecture to offer network agility. Here, an elastic optical network is referred to as the optical network that can adapt the channel bandwidth, data rate, and transmission format for each traffic demand in order to offer maximum throughput. In elastic filterless networks, the presence of unfiltered signals resulting from the drop-and-continue node architecture must be considered as an additional constraint in the RSA problem. In this paper, first, the RSA problem in elastic filterless networks is formulated by using an integer linear program to obtain optimal solutions for small networks. Due to the problem complexity, two efficient RSA heuristics are also proposed to achieve suboptimal solutions for larger networks in reasonable time. Simulation results show that significant bandwidth savings in elastic filterless networks can be achieved compared with the fixed-grid filterless solutions. The proposed approach is further tested in multi-period traffic scenarios and combined with periodical spectrum defragmentation, leading to additional improvement in spectrum utilization of elastic filterless optical networks.

1+1 Dedicated Optical-Layer Protection Strategy for Filterless Optical Networks

We propose a dedicated optical-layer protection strategy for filterless optical networks offering a 100% protection ratio by introducing a limited number of wavelength selective components at selected intermediate nodes. A comparison with conventional active photonic switching networks is presented. The results show that the proposed 1+1 protection for filterless networks exhibits a clear cost advantage at similar wavelength usage compared to active switching solutions.

Flexible Bandwidth Allocation in Filterless Optical Networks

We introduce the new concept of an elastic filterless optical network and propose an efficient heuristic algorithm for solving the static routing and spectrum assignment problem. Our simulation results obtained for different network topologies under multi-period traffic show increasing bandwidth savings with the growth of traffic load compared to a fixed-grid scenario. We also show the benefits of periodical spectrum defragmentation.

Filterless architecture for coherent undersea networks

Active photonic switching components, such as reconfigurable optical add/drop multiplexers (ROADMs), cannot be deployed at the branching units (BUs) in submarine networks, which limits the flexibility of the undersea networks. In this regard, the filterless optical network architecture based on passive broadcast-and-select nodes and coherent transceivers at the edge terminals can be considered as a promising solution. In this paper we propose and evaluate a filterless network architecture for a trunk and branch undersea network topology. The performance is compared with a conventional solution in terms of cost and wavelength consumption. And it is shown that the filterless architecture can bring significant cost savings for both the terminals and line equipment while offering the same agility as the conventional network architecture.

Optimal design of cost- and energy-efficient scalable passive optical backbone networks

We propose an optimization model minimizing number of wavelengths in passive optical backbone networks and obtaining the same resource usage as in networks based on active switching while reducing both cost and power consumption.

Proposed filterless architecture and control plane for emerging flexible coherent networks

Recent developments in coherent modem performance and digital signal processing (DSP) technologies have opened the opportunity for new agile network architectures [1, 2]. The filterless network concept has been proposed in [3] and it is shown that they are more cost-effective and reliable compared to active optical switching networks. Filterless optical networks use broadcast-and-select techniques in which passive non-filtered optical splitters and combiners are used for channel add-drop and fiber link interconnection. Furthermore, DSP-based coherent modems are complementary foundational technologies for flexible optical networking owing to their properties of dynamic impairment compensation, performance monitoring and tuneability. The resulting network architecture makes an attractive candidate solution for flexible optical networking [4]. In this talk, we review the recent progress in filterless optical network design and control [5]–[7]. In the first part, filterless architectural solutions are proposed for different network topologies and compared to active photonic switching solutions. A cost and performance analysis of filterless network solutions with 1 + 1 optical layer protection is also presented. In the second part, we present a control plane for filterless optical networks and describe its main characteristics through a performance study. Our results show that passive filterless networks can be considered as a cost effective and simpler alternative to active optical switching networks whenever traffic loading is not approaching full network capacity.