Automatic control method for flatness of coherent multi-wavelength light source

The invention belongs to the technical field of photoelectronics, and discloses a method for controlling the flatness of a coherent multi-wavelength light source, which comprises the following steps of: generating optical frequency combs through a laser and a modulator, driving a radio frequency signal by using a power divider and a phase shifter, adjusting the phase of the radio frequency signal, selecting three optical frequency combs through an optical filter, according to the invention, the optical comb can be rapidly adjusted to a flat state when the optical comb generated by the cascade modulator is not flat in an initial state, the optical comb can be used for adjusting the planarization of the optical comb generated by cascade connection of the MZM and the two-stage PM, and the optical comb can be adjusted to be flat. According to the scheme of generating the optical comb in the cascade mode, adjustment can be perfectly completed by adopting any number of PMs, automatic adjustment of the flatness of t