Power Stabilization System Of Laser Based On Acousto-optic Modulator

In the field of optical radiation measurement, some advanced technology, such as low temperature, ultra low temperature, super conductance and double layer cold shield, have been used in cryogenic radiometer, which has greatly improved the accuracy of optical radiation measurement. In order to maximize the advantages of cryogenic radiometer, the laser source is required to be able to output laser signal with high stable power. Normally, due to the injection current, operating temperature, mode jump, gain factor, and other factors, the fluctuation of the laser output power is not less than 1%. In order to meet the requirement of the practical application, laser power stability control system needs to be developed, so that it can output more stable laser signal. Based on the application background, this paper designs a laser power stabilization control system based on acousto-optic modulation, and completed Verification work of the system function by building an actual system.On the basis of the research on stability control technology of laser output power, this paper illustrates the advantages and limitations of relevant technology, and then briefly introduces the development of laser, and explains the classification of laser. After analysis of the output power fluctuation of He-Ne laser and semiconductor laser, this paper presents all kinds of power stability control technology and mainly introduces external acousto-optic modulation technology. Because external modulation can achieve more stable laser signal, so this paper choose acousto-optic modulation as the controller to stable laser power, the laser power stability control system is mainly composed of optical devices, photoelectric amplifier and feedback controller. The feedback controller uses FPGA as the main control chip, and uses PID algorithm to complete the control function of laser output power. According to the experimental data obtained from different experimental conditions, the experimental data analysis shows that this system can be applied to different wavelengths of laser control, and it can work stably for a long time. The output laser power stability of this system is better than 0.05%/h, and the laser signal can be used as the stable light source for the precision measurement system such as cryogenic radiometer.