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Wavelength Division Multiplexing (wavelength + division_multiplexing)

Distribution by Scientific Domains

Engineering	75%

Selected Abstracts

Minimizing the cost of placing and sizing wavelength division multiplexing and optical crossconnect equipment in a telecommunications network

NETWORKS: AN INTERNATIONAL JOURNAL, Issue 4 2005
Belén Melián
Abstract Cost reduction is a major concern when designing optical fiber networks. Multiwavelength optical devices are new technology for increasing the capacity of fiber networks while reducing costs, when compared to installing traditional (e.g., SONET) equipment and new fiber. In this article we discuss the development of a metaheuristic method that seeks to optimize the location of Wavelength Division Multiplexing (WDM) and Optical Crossconnect (OXC) equipment in fiber networks. The procedure combines ideas from the scatter search, tabu search, and multistart methodologies. Computational experiments with both real-world and artificial data show the effectiveness of the proposed procedure. The experiments include a comparison with a permutation-based approach and with lower bounds generated with CPLEX. © 2005 Wiley Periodicals, Inc. NETWORKS, Vol. 45(4), 199,209 2005 [source]

Survivable wavelength-routed optical network design using genetic algorithms

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 3 2008
Y. S. Kavian
The provision of acceptable service in the presence of failures and attacks is a major issue in the design of next generation dense wavelength division multiplexing (DWDM) networks. Survivability is provided by the establishment of spare lightpaths for each connection request to protect the working lightpaths. This paper presents a genetic algorithm (GA) solver for the routing and wavelength assignment problem with working and spare lightpaths to design survivable optical networks in the presence of a single link failure. Lightpaths are encoded into chromosomes made up of a fixed number of genes equal to the number of entries in the traffic demand matrix. Each gene represents one valid path and is thus coded as a variable length binary string. After crossover and mutation, each member of the population represents a set of valid but possibly incompatible paths and those that do not satisfy the problem constraints are discarded. The best paths are then found by use of a fitness function and these are assigned the minimum number of wavelengths according to the problem constraints. The proposed approach has been evaluated on dedicated path protection and shared path protection. Simulation results show that the GA method is efficient and able to design DWDM survivable real-world optical mesh networks. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Signal Dependence of Cross-Phase Modulation in WDM Systems

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 2 2000
Lutz Rapp
In intensity modulated direct detection wavelength division multiplexing (WDM) systems, the effect of cross-phase modulation (XPM) combined with groupvelocity dispersion causes signal distortion, which depends on the transmitted signals. The influence of the mutual dependence of these signals on the resulting degradation of the system performance is investigated theoretically and by means of simulations. Considering the propagation of two digital signals, the eye-closure penalty is determined for different bit patterns and consequences for system design are pointed out. An approximation method is described in order to provide a better understanding of the signal dependence of XPM. Finally, a technique reducing the impact of XPM on data transmission in WDM systems is proposed. [source]

Clustering-based scheduling: A new class of scheduling algorithms for single-hop lightwave networks

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 8 2008
Sophia G. Petridou
Abstract In wavelength division multiplexing (WDM) star networks, the construction of the transmission schedule is a key issue, which essentially affects the network performance. Up to now, classic scheduling techniques consider the nodes' requests in a sequential service order. However, these approaches are static and do not take into account the individual traffic pattern of each node. Owing to this major drawback, they suffer from low performance, especially when operating under asymmetric traffic. In this paper, a new class of scheduling algorithms for WDM star networks, which is based on the use of clustering techniques, is introduced. According to the proposed Clustering-Based Scheduling Algorithm (CBSA), the network's nodes are organized into clusters, based on the number of their requests per channel. Then, their transmission priority is defined beginning from the nodes belonging to clusters with higher demands and ending to the nodes of clusters with fewer requests. The main objective of the proposed scheme is to minimize the length of the schedule by rearranging the nodes' service order. Furthermore, the proposed CBSA scheme adopts a prediction mechanism to minimize the computational complexity of the scheduling algorithm. Extensive simulation results are presented, which clearly indicate that the proposed approach leads to a significantly higher throughput-delay performance when compared with conventional scheduling algorithms. We believe that the proposed clustering-based approach can be the base of a new generation of high-performance scheduling algorithms for WDM star networks. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Burst scheduling for differentiated services in optical burst switching WDM networks

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 2 2004
David Q. Liu
Abstract Optical burst switching (OBS) is one of the most important switching technologies for future optical wavelength division multiplexing (WDM) networks and the Internet. The model of differentiated services has been proposed to support quality of service (QoS) in the IP-based Internet. It is also very important to have differentiated service support in OBS networks. When the burst scheduling in an OBS network is set up appropriately, network can support differentiated services. In this paper, we proposed a new burst scheduling scheme, called differentiated scheduling with identical priority offset time (DSIPO). In DSIPO, the same priority offset time is used for all the bursts destined to the same edge node regardless of their priorities. Differentiated services in terms of burst loss probability are achieved by processing the control packets of higher priority class bursts, thus reserving resources for their data bursts, more promptly upon their arrival than those of lower priority class bursts. Each intermediate (core) node can adjust the burst loss probabilities of various burst classes by choosing its own differentiated processing delay value for each priority class or its own differentiated processing delay difference value between any pair of adjacent priority classes. We model and analyse DSIPO in terms of the burst loss probability for each priority class with simulation validation. The performance of DISPO is evaluated by simulation. Copyright © 2004 John Wiley & Sons, Ltd. [source]

High raman gain of dispersion compensation fiber using RZ-DPSK format for long-haul DWDM transmission system

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2010
Hsiu-Sheng Lin
Abstract We investigated the transport of a 16 channels 40 Gb/s dense wavelength division multiplexing (DWDM) system which uses high Raman gain of dispersion compensation fiber (DCF) for long-haul DWDM transmission. Using the return to zero differential phase shift keying (RZ-DPSK) modulation format with an optimized dispersion compensation format, we demonstrate DWDM transmission with a capacity of 640 Gb/s with 0.4 nm channel spacing over 4500 km of transmission fiber. The transmission system structure uses 120 km single mode fiber and 30 km DCF for thirty spans in the C band wavelength range and a Raman Amplifier with high Raman gain to achieve long-haul transmission. We also used enhanced forward error correction for high capacity transmission over several thousand kilometers with the RZ-DPSK modulation format. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2548,2551, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25552 [source]

Optical fiber sensor for localizing heating positions in multiple points using multichannel gratings with phase sampling and wavelength division multiplexing techniques

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2008
Li Xia
Abstract An optical fiber sensor system with multichannel fiber Bragg gratings (FBGs) is proposed. The gratings are designed and fabricated by phase sampling technique within strongly chirped phase masks. The sensing application can be realized at multiple points through wavelength division multiplexing (WDM) technique. It means that the different point can be monitored by different gratings, which occupies different wavelength region, according to the central pitch and chirp coefficient of phase masks. The heating position with high resolution can be analyzed through three corresponding channel shifts in the multichannel profile. In our experiment, the two multichannel gratings with channel spacing of 0.8 and 1.6 nm, respectively, are fabricated and used for sensing in two points. At last, the 400 ,m accuracy of localizing the heating position is achieved. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2951,2954, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23832 [source]