Is it a good idea to design WDM networks to minimize the number of wavelengths used?

In this paper, we study the routing and wavelength assignment (RWA) tasks in WDM mesh networks with wavelength conversion capabilities. We solve the routing and wavelength assignment sub-problems as a single problem, rather than separating them into two separate problems. We use two different optimization criteria: (1) minimize the number of wavelength conversions used; and (2) minimize the number of wavelengths used. Each of these problems is solved by using a method based on the Dijkstra algorithm, sequentially on one connection at a time. We study and comment on the performance of the algorithms for different network topologies and traffic scenarios.