An all-digital design method consisting of a laser drive circuit for gradually modulating the frequency, pulse width, and amplitude of the output of semiconductor laser is demonstrated. Field programmable gate arrays (FPGAs) and accurate delaying chip are used to generate the pulse. The repetition rate and pulse width of the laser pulse gradually adjust from 1 to 10 kHz and 700 ps to 3 ns, respectively. Furthermore, the time of the rising and falling edges for the laser pulse is less than 800 ps.