This paper analyzes and demonstrates a simplified frequency quadrupling configuration for optical millimeter-wave (mm-wave) generation, in which the electrical phase shifter and optical filter are omitted. Theoretical analysis is given to reach the optimum operating conditions including direct current (DC) bias voltage, optical transmission point of the dual-parallel Mach-Zehnder modulator (MZM) bias voltage, optical transmission point of the dual-parallel Mach-Zehnder modulator (DP-MZM), amplitude of the radio frequency (RF) driving signal and the impact of the extinction ratio (EF) on the optical sideband suppression ratio (OSSR) and radio frequency spurious suppression ratio (RFSSR). Experiments prove an OSSR of 15 dB and an RFSSR of 26 dB for the new frequency quadrupling scheme at 6 GHz, 8 GHz and 10 GHz of RF driving signal without any electrical phase shifter or optical filter. This system exhibits the advantage of low wavelength dependence and large frequency tunable range.