We propose and investigate a novel technique for the generation of millimeter-wave(mm-wave),i.e.,frequency sixuplexing technique.The proposed technique adopts two cascaded Mach-Zehnder modulators(MZMs).The first MZM,biased at minimum transmission,is only used for the odd-order optical harmonic generation,and then by using a second MZM,biased at maximum transmission,all odd-order optical harmonics are suppressed.As an example,we consider a radio frequency(RF) at 10 GHz,which drives the MZMs;and a mm-wave signal at 60 GHz,i.e.a frequency sixupler,is obtained.The generated mm-wave signal is robust to fiber chromatic dispersion.The proposed technique is verified by experiments.