Broadband optical frequency comb generation method based on cascade connection of DPMZM and two IMs

The invention discloses a broadband optical frequency comb generation method based on cascade connection of a DPMZM and two IMs. The problems that an optical frequency comb generated in the prior art is small in spectral bandwidth and low in out-of-band rejection ratio are solved. The method comprises the following steps: generating a radio frequency signal; setting a direct current bias voltage of the modulator; inputting an optical carrier signal; generating a modulated optical signal; counteracting +/-1-order sideband signals generated by the two sub-modulators; suppressing a high-order sideband signal; a 10-line broadband optical frequency comb is generated; and a 50-line broadband optical frequency comb is generated. Through the main modulator of the DPMZM, +/-1-order sideband signals generated by the two sub-modulators are offset, the DPMZM outputs +/-3-order sidebands, the spectral bandwidth of the optical frequency comb is increased, a band-pass optical filter is added behind the DPMZM, and the out-of