Repetition frequency locking device and method

The invention provides a repetition frequency locking device, which comprises a first beam splitter, a fine adjustment part, a rough tracking part, a digital-to-analog conversion circuit and a control part, wherein the fine adjustment part is used for carrying out fine adjustment on the repetition frequency of a laser and comprises a first photodiode, a high-voltage difference frequency signal generation circuit and piezoelectric ceramic, and the piezoelectric ceramic stretches or shrinks under the drive of a high-voltage difference frequency signal to change a position of an optical lens in order to realize fine adjustment; the rough tracking part is used for carrying out rough tracking on the repetition frequency of the laser and comprises a precise step motor and a step motor driver; the digital-to-analog conversion circuit is used for converting the high-voltage difference frequency signal into a corresponding digital signal; and the control part is used for controlling the step motor driver according to the digital signal and a preset program to realize control of the rough adjustment. The invention also provides a repetition frequency locking method. According to the device and the method, the precise adjustment within the larger range can be realized, and the repetition frequency of the laser can be locked at the predetermined repetition frequency.