Priority Based Dispersion-Reduced Wavelength Assignment for Optical Networks

Dispersion in optical fiber degrades the quality of signal in optical networks. Although the use of dispersion compensating fiber (DCF) reduces the effects of dispersion, it is expensive and has more propagation loss compared to step-index fiber (SIF). In this paper, we propose a priority based dispersion-reduced wavelength assignment (PDRWA) scheme to reduce overall dispersion in optical network. In this scheme, the connection requests having a same source-destination (s-d) pair are groomed first to avoid intermediate optical-electrical-optical (O/E/O) conversation and then these groomed connection requests with longer lightpath are assigned the wavelengths having lesser dispersion and the wavelengths having a higher dispersion are assigned to the lightpaths with shorter distance. If the connection requests are assigned to the wavelengths using such constraint on dispersion, the overall dispersion in the network can be reduced to a great extent, which will in turn lead to better performance of the network in terms of overall signal quality (Q-factor) without increasing network setup cost. The performance analysis of the proposed scheme using SIF is conducted with different channel speeds (10, 40 and 100 Gbps) in terms of total dispersion and compared the same with the use of DCF. Furthermore, we have studied the overall Q-factor in the network with different channel speeds and considering polarization mode dispersion (PMD) effect using SIF and DCF.