Digital control method for laser power stabilization

A digital control method for laser power stabilization, comprising:

• generating a light beam by using a laser light source, conditioning the light beam into a linearly polarized light beam by using a first polarizer, allowing the linearly polarized light beam to pass through an acousto-optic modulator (AOM), and then filtering the linearly polarized light beam by using a second polarizer;
• changing a polarization direction of a filtered linearly polarized light beam by using a rotatable λ/2 wave plate, and inputting the filtered linearly polarized light beam into a polarization beam splitter, wherein the polarization beam splitter divides the linearly polarized light beam into inner-loop optical power and outer-loop optical power, the inner-loop optical power is used for power control, and the outer-loop optical power is used for an output application;
• setting light transmittance of the AOM as a preset value, and controlling a temperature of the AOM by using a temperature controller to calibrate a relationship between a temperature value of the AOM and the inner-loop optical power;
• setting a target light intensity corresponding to an inner-loop initial optical power based on the inner-loop initial optical power;
• converting, by a signal conditioning unit, the temperature value into a first electrical signal, converting, by a photoelectric detector, the inner-loop optical power into a second electrical signal, then converting, by an analog to digital converter (ADC), the first electrical signal and the second electrical signal into a first digital signal and a second digital signal respectively, and inputting the first digital signal, the second digital signal and the target light intensity to a digital proportion integration differentiation (PID) controller to obtain a PID output signal;
• and
• converting, by a digital to analog converter (DAC), the PID output signal into an analog signal, and adjusting, by a power controller, the AOM based on the analog signal to output a stabilized outer-loop optical power.