Abstract: The crosstalk of two OXC topologies with multicasting capability is analyzed. Then the output power equation for the topologies are derived in the worst case. According to the equations, the total crosstalk as a function of the number of wavelengths and the number of input/output fibers is studied. From the comparison we can find that the crosstalk of the two topologies performs almost equally for multicast connections and the crosstalk of teh OXC based on MOSaD is lower than that of the OXC based on SaD for unicast connections. In the condition of state-of-art technologies, when the number of wavelengths equals 4 and the number of input/output fibers equals 2, the crosstalk is as much as -17dB in the case of multicasting.

Key words: wavelength division multiplexing, crosstalk, optical cross connect(OXC), optical switches, multicast