Sharing wavelength converters in optical switching fabrics: When, how, and which kind of?

In this paper a parametric cost model is applied to compare switching fabrics sharing a reduced number of fixed/tunable wavelength converters with a fully equipped architecture. This cost model can be used to evaluate in which switch configuration a sharing scheme leads to effective cost reduction, according to the cost parameters. Sample results show how sharing wavelength converters is not always the best choice, in particular when the cost ratio between a wavelength converter and an optical gate is low. Actually sharing converters requires a relevant number of additional optical gates. The sharing leads to reduced cost when the number of fibers/wavelengths is not very high, while the fully equipped architecture is often preferable for large switch sizes. Furthermore, fixed wavelength converters lead to further cost saving in many cases.