A novel frequency quadrupling scheme based on a dual parallel Mach-Zehnder modulator (MZM) for the generation of optical millimeter signal and modulation of the vector signal is demonstrated. The traditional frequency quadrupling modulation scheme, which modulates data on both +2 and -2 order optical sidebands and will cause the constellation overlapping after photodetector (PD) detection, can only carry the on-off keying data format such as not return to zero (NRZ). The proposed scheme encodes the electrical vector signal on the -1 order optical sideband, and a pure radio frequency (RF) tone at +3 order optical sideband. Therefore, phase and amplitude information will be correctly preserved after detection. Besides, a frequency quadrupling scheme is employed to reduce the bandwidth requirements of the electrical and optical components of the transmitter. A proof of concept and simulation is conducted by using a 6.25×108 symbol/s QPSK signal at a carrier frequency of 60 GHz , which indicates that the error vector magnitude (EVM) penalty is negligible after transmission over 20-km single-mode fiber (SMF).