Fig. 1. High-flat terahertz broadband optical frequency comb generator system structure diagram based on electro-optical modulator

Fig. 2. Structure diagram of optical frequency comb generated by dual-drive Mach-Zender modulator

Fig. 3. The simulation results of the proposed OFC scheme. (a) Output spectrum of DDMZM; (b) output spectrum of PM; (c) output spectrum of MZM; (d) localized amplification spectrum of MZM output

Fig. 4. The influence of driving signal amplitude difference and DC bias voltage difference on the flatness of the optical comb under different conversion efficiencies. (a) The influence of attenuators on the flatness of optical combs; (b) the influence of DC bias voltage difference on the flatness of optical combs ; (c) the influence of DC bias voltage difference on the flatness of the optical comb when $\mathrm{\Delta }A=\mathrm{\pi }/\mathrm{4}$; (d) the influence of the amplitude difference of the driving signal on the flatness of the optical comb when $\mathrm{\Delta }A=\mathrm{\pi }/\mathrm{4}$

Fig. 5. Output spectra when $\mathrm{\Delta }A=\mathrm{0.2}\mathrm{\pi }$,$\mathrm{\Delta }\theta =\mathrm{0.3}\mathrm{\pi }$

Fig. 6. Output spectra at different microwave drive signal frequencies

Fig. 7. Curves of the number of combs versus different power deviations

Fig. 8. Effect of MZM bias drift on OFC flatness

Fig. 9. Optical carrier terahertz transmission system based on optical frequency comb

Fig. 10. Relationship curve between BER and PD input optical power of a single-channel 16QAM signal

Fig. 11. Relationship curve between BER and PD input optical power of multi-channel 16QAM signal

Table 1. System simulation parameters

Table 2. Highest and lowest power differences between modulators