Design Of WDM Networks Research Articles

Design of hierarchical crossconnect WDM networks employing a two-stage multiplexing scheme of waveband and wavelength

The authors propose a design method for hierarchical crossconnect wavelength-division-multiplexed networks employing a two-stage multiplexing scheme of waveband and wavelength, in order to reduce the complexity and size of optical crossconnect at the nodes. The waveband is formed by grouping lightpaths with the same destination in a network. The authors present an integer linear programming formulation for the routing and grouping of lightpaths, and a heuristic design method is also proposed as a practical method to find a design solution for general large-scale networks. It is found that the proposed design method can largely reduce crossconnect requirements, although it slightly increases the wavelength requirements.

Design of survivable WDM networks for carrying ATM traffic

Wavelength-division multiplexed networks using wavelength-routing are considered to be potential candidates for the next generation of wide-area backbone networks. In these networks, messages are carried in all-optical form using lightpaths. ATM is a widespread architecture and it is natural to extend the two-level connection architecture of ATM to the three-level connection architecture of optical-ATM networks. The three-level connection architecture is realized by providing a LP network under the virtual path network, to meet the bandwidth requirements of the virtual paths (VPs). Fault handling in these networks is of prime importance due to the nature and volume of traffic that these networks carry. Faults can be handled by rerouting the failed LPs in such a way that, failures are transparent to the VPs at the upper layer. Our work aims at designing a LP network with fault tolerance capability for an ATM network with an underlying optical layer. The primary network is designed with the objective of minimizing the number of fibers. The restoration network is designed to survive single link failures with the objective of minimizing the number of fibers. We develop design methods based on heuristics, and verify their effectiveness through simulation experiments.

Design of optical WDM networks. LAN, MAN and WAN architectures [Book Review

Design of optical WDM networks. LAN, MAN and WAN architectures [Book Review

Transmission performance of high bit rate spectrum-sliced WDM systems

We simulate transmission of a spectrum-sliced WDM channel operating at high bit rates (e.g., 622 to 2488 Mb/s). We calculate the bit error rate using the non-Gaussian statistics of thermal light sources that are commonly used in spectrum slicing and account for the effects of fiber dispersion. We evaluate the tradeoff in optical slice linewidth between signal-to-excess optical noise ratio and dispersion penalty in spectrum-sliced WDM systems, and determine the channel slicewidth that minimizes transmission penalty for a given link length and bit rate. We compare our simulations against the measured performance of a 1244 Mb/s channel over 20 km of fiber. The results in this paper provide useful information for the design of spectrum-sliced WDM networks.

Modeling of four-wave mixing and gain peaking in amplified WDM optical communication systems and networks

A theoretical model is presented for analyzing the propagation of densely spaced WDM optical signals through a cascade of erbium-doped fiber amplifiers and single-mode optical fibers with nonuniform chromatic dispersion. By combining a numerical solution for the EDFA and an analytical expression for FWM components generated through the cascade, the model allows a realistic system analysis which includes gain peaking effect, amplified spontaneous emission accumulation and the effect of dispersion management on the four-wave mixing efficiency. The FWM power distribution at the end of the multi-amplifier transmission link is computed taking into account the phase relation between FWM light amplitudes generated within different sections of the link. The transmission of many WDM channels, evenly spaced around 1547.5 nm, has been analyzed for various dispersion management techniques and propagation distances. Numerical results point out the importance of such a model for a realistic design of WDM optical communication systems and networks. A proper choice of chromatic dispersion, amplifier characteristics, span length, input signal powers and wavelengths, combined with the use of gain equalizing filters, allows to maximize the transmission distance ensuring acceptable signal-to-noise ratio (SNR) and limited SNR variation among channels.