Abstract-This paper presents the results of a crosstalk analysis of four optical wavelength division multiplexed (WDM) cross-connect (OXC) topologies. An optimal set of parameters is determined to reduce the total crosstalk. The scalability of the topologies is presented in terms of wavelengths and input fibers. The total crosstalk in function of the number of cascaded OXC's is compared for the four topologies.Index Terms-Optical communication, optical crosstalk, optical cross connect (OXC), optical switches, optical wavelength conversion, wavelength division multiplexing (WDM).