Impact of 3R wavelength converters on the blocking probability of WDM networks with finite signal impairment threshold

We consider WDM mesh networks with finite signal impairment threshold (SIT) and estimate the minimum requirement of 3R wavelength converters (3R-WCs) per node. We find that the marginal utility of 3R-WC diminishes rapidly and relatively small number of 3R-WCs is enough to enhance the network performance to that of a WDM network with infinite SIT and wavelength converters at all the channels per node.