Sweep frequency laser, control method thereof and optical coherence tomography system

The embodiment of the invention provides a sweep frequency laser, a control method thereof and an optical coherence tomography system, and the sweep frequency laser comprises a light beam generation assembly which is used for emitting a first light beam; the acousto-optic deflector comprises an ultrasonic generating element and a crystal, the crystal comprises a first surface and a second surface, and the first surface receives the first light beam; the ultrasonic generating element is used for transmitting a first ultrasonic signal to the crystal, and the first ultrasonic signal is a first nonlinear chirp signal; under the driving of the first nonlinear chirp signal, the medium in the crystal forms a grating which changes along with the frequency of the first nonlinear chirp signal, so that the first light beam is diffracted to obtain first-level diffracted light, and the first-level diffracted light is emitted from the second surface; and the wavelength selective reflection element is used for reflecting th