in general , in one aspect , the disclosure describes a multi - stage switch having at least one ingress switch module to receive data and to generate frames that are transmitted as a wavelength division multiplexed signal . the multi - stage switch further includes a core switch module operatively connected to receive the wavelength division multiplexed signal from the at least one ingress switch module and to switch the frames . the multi - stage switch additionally includes at least one egress switch module to receive the wavelength division multiplexed signal from the core switch module and to transmit data .