N. Antoniades

Cascadability of passband-flattened arrayed waveguide-grating filters in WDM optical networks

The cascadability of passband-flattened arrayed waveguide-grating (AWG) filters is studied using experimental and theoretical transfer functions. The formalism is general and can be used to cascade any type of filter at any channel spacing. For example, modeling indicates that transmission through 100 such AWG (de)multiplexers at 200-GHz channel spacing, assuming 10-Gb/s data streams introduces distortion-induced penalties below the widely acceptable 0.3-dB limit, provided that certain filter design requirements are satisfied. All simulations focus on the filter cascadability and central frequency misalignment effects, and neglect nonlinearities and crosstalk.

Multicast Routing Algorithms Based on

We use novel ldquolight-tree balancing techniquesrdquo to investigate the problem of provisioning multicast sessions in metropolitan all-optical networks. The Q-factor for every path of a derived light-tree is calculated taking into account several physical layer constraints in the network and using a Q-budgeting approach. Based on the above performance, tree balancing techniques are applied to maximize the number of multicast connections that can be admitted to the network.

Q

In this letter, we report on the effect of polarization-dependent loss (PDL) on the performance of a metro wavelength-division-multiplexing transparent optical network. We show that dynamic channel-by-channel power equalizers are needed in such networks for compensating the significant amount of PDL-induced channel power divergence that accumulates in transparent optical paths.

-Factor Physical-Layer Constraints in Metro Networks

In this work, we present a detailed study on the extraction procedures for rate equation parameters. Parameters related to the chirp characteristics are extracted directly from chirp measurements. Moreover, the procedures have been applied for the characterization of directly modulated lasers (DMLs) with different characteristics. The laser dynamics were accurately simulated as shown by comparing the measured and simulated results for both chirp and power waveforms. The extracted parameters were then used in transmission simulation to identify the best fiber choice for metropolitan area networks utilizing DMLs. This work can be a useful tool whenever the influence of DML characteristics on the overall performance of a system must be accurately evaluated.

PDL-induced channel power divergence in a metro WDM network

This paper presents a theoretical study of the transient power fluctuations of wavelength add-drop multiplexer chains caused by the dynamic interaction of servo-controlled attenuators and saturated erbium-doped fiber amplifiers. The mechanisms responsible for this oscillatory behavior are identified and remedies are proposed.

Measurements of laser rate equation parameters for simulating the performance of directly modulated 2.5 Gb/s Metro area transmission systems and networks

We experimentally demonstrate error free performance of a simple ring-based Ethernet Passive Optical Network (EPON) architecture that supports truly shared LAN capability among users as well as a fully distributed dynamic bandwidth allocation DBA scheme. The proposed distributed architecture can also be utilized as a packet-based mobile backhaul transport network to backhaul emerging mobile services across the PON-based fiber infrastructure. Utilizing PON access infrastructure as a mobile backhaul enables a seamless migration path to fixed-mobile convergence solutions.

Transient effects in wavelength add-drop multiplexer chains

This letter presents an accurate model for the evaluation of the error probability of transparent multiwavelength optical networks with cascaded optical multiplexers/demultiplexers (MUX/DMUXs). The error probability evaluation takes into account arbitrary pulse shapes, arbitrary optical MUX/DMUX and electronic lowpass filter transfer functions, intersymbol interference, and the accurate (non-Gaussian) noise probability density function at the output of the optically preamplified direct-detection receiver. As an example, the model is used to study the cascadability of arrayed waveguide grating routers in conjunction with nonreturn-to-zero pulses.

Experimental demonstration of a distributed ring-based EPON architecture

This work investigates the static impairment-aware multicast routing and wavelength assignment (IA-MC-RWA) problem for transparent Wavelength Division Multiplexing (WDM) metro networks. The IA-MC-RWA problem, known to be NP-complete, is first formulated mathematically as an integer linear program (ILP) taking into account a number of impairments encountered by the multicast connections at the physical layer. Efficient heuristics are also developed to solve the multicast routing problem with practical network size parameters. To evaluate the heuristics, their optimality is first examined by comparing their performance results to the results of the ILP for a small-sized network. Their performance is subsequently evaluated over a practical-sized problem. The proposed Q-based Steiner Tree (QBST) heuristic that takes the physical layer impairments (PLIs) into consideration during the provisioning phase of the multicast tree, outperforms the rest of the multicast routing heuristic algorithms developed for comparison purposes and provides results closer to the optimal compared to the ILP.

Error probability of transparent optical networks with optical multiplexers/demultiplexers

This paper investigates the problem of protecting multicast sessions in optical networks utilizing a novel cycle-based heuristic algorithm called Q-based p-Cycles Heuristic (QBPCH), that is used for the decomposition of the graph network into a set of p-cycles, while taking into account the physical layer impairments (PLIs) via a Q-budgeting approach. In this technique the length of these cycles is constrained in order to limit the effect of the impairments on the protection paths. The proposed scheme exhibits improved performance in terms of blocking probability, when compared to another proposed heuristic, namely p-Cycles Heuristic (PCH), that aims at decomposing the graph network into a set of p-cycles that maximizes the number of straddling links in the network. Both proposed schemes are also compared to a traditional ring cover heuristic (RC) and to a Hamiltonian cycle (HC) approach and it is shown that QBPCH performs the best in terms of blocking probability when the PLIs are considered.

Impairment-aware multicast session provisioning in metro optical networks

Due to reduced operational and equipment costs, time division multiplexed (TDM)-based passive Optical Network (PON) access solutions including Gigabit PON (GPON) and Ethernet PON (EPON) have been widely accepted as a viable technology for the implementation of fiber-to-the-x (FTTx) solutions, and are being deployed globally. Users are increasingly requiring more bandwidth for high end applications and at the same time greater mobility. The convergence of fiber and wireless systems is seen as the optimum solution to offer the combination of the fiber capacity and the wireless mobility. PON has been proposed as a backhaul for wireless. Typical architectures are traditionally deployed as tree topologies. However, tree-based topologies have several inherent drawbacks such as inability to support a truly shared Local Area Network (LAN) capability among end users. In this paper, we propose scalable ring-based architectures that offer truly shared LAN capability as well as dynamic bandwidth allocation. These architectures are ring-based as well as hybrid, combination of tree-based and ring-based. These flexible architectures can be used as the back-haul to wireless by incorporating the base stations in the ONU locations. Our proposed hybrid PON ring architecture is scalable to 78 ONUs without the use of any amplifiers and in addition, the basic ring architecture and in turn the hybrid one is transparent to protocols and data rates and hence allows for greater BW flexibility as well as greater number of serviced end-users.