An optical network includes receiving inter-rack traffics from transmitter racks, converting by transmitters the inter-rack traffics to respective wavelength division multiplexing WDM optical signals, receiving and routing by a cyclic interleaver the optical signals from the transmitters to output ports in a cyclic manner, converting respective routed optical signals from the cyclic interleaver into respective electrical signals, and demodulating OFDM formats from respective converted optical signals containing signals for respective receiver racks.