According to one embodiment, a system for transmitting an optical signal comprises a traffic distribution circuit configured to distribute traffic to a plurality of wavelength division multiplexer (WDM) modules. The system further comprises a first WDM module and a second WDM module. The first and second WDM modules each comprise a plurality of tunable optical transmitters, with each transmitter associated with a different wavelength band of a plurality of wavelength bands. Each transmitter in the first and second WDM modules is also tuned to transmit optical signals in channels included within the associated wavelength band of the transmitter. The first and second WDM modules each comprise a multiplexer configured to combine the optical signals transmitted from the plurality of transmitters into optical signals. The system further comprises a cyclic multiplexer configured to combine the optical signals from the first and second WDM modules into an optical output signal.