Browsing by Subject "Wavelength converters"

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Open Access
State aggregation-based model of asynchronous multi-fiber optical switching with shared wavelength converters
(Elsevier, 2013) Akar, N.; Raffaelli, C.; Savi, M.
This paper proposes new analytical models to study optical packet switching architectures with multi-fiber interfaces and shared wavelength converters. The multi-fiber extension of the recently proposed Shared-Per-Input-Wavelength (SPIW) scheme is compared against the multi-fiber Shared-Per-Node (SPN) scheme in terms of cost and performance for asynchronous traffic. In addition to using Markov chains and fixed-point iterations for modeling the mono-fiber case, a novel state aggregation technique is proposed to evaluate the packet loss in asynchronous multi-fiber scenario. The accuracy of the performance models is validated by comparison with simulations in a wide variety of scenarios with both balanced and imbalanced input traffic. The proposed analytical models are shown to remarkably capture the actual system behavior in all scenarios we tested. The adoption of multi-fiber interfaces is shown to achieve remarkable savings in the number of wavelength converters employed and their range. In addition, the SPIW solution allows to save, in particular conditions, a significant number of optical gates compared to the SPN solution. Indeed, SPIW allows, if properly dimensioned, potential complexity and cost reduction compared to SPN, while providing similar performance.
Open Access
TSCP: a tabu search algorithm for wavelength converting node placement in WDM optical networks
(IEEE, 2005) Şengezer, Namık; Karasan, Ezhan
Sparse wavelength conversion can increase the performance of all-optical wavelength division multiplexing (WDM) networks signi cantly by relaxing the wavelength continuity constraint. In this paper, we study the wavelength converter placement problem in multi- ber networks with static traf c demands. We present a tabu search based heuristic algorithm. The objective of the algorithm is to satisfy all the traf c demands with the minimum total cost of bers achieved in the full conversion case, by placing minimum number of wavelength converting nodes. We also implement a greedy algorithm and compare the performances of these converter placement algorithms with the optimum solutions on a sample network. The Tabu search based algorithm achieves the optimum solution in 72% of the test cases and it increases the average number of wavelength converting nodes by less than 10% with respect to the optimum solution. The effect of the utilized routing scheme on the generated solutions and the correlation between the converter node locations and the amount of traf c passing through the nodes are also investigated.