Achievement Exhibition

Ultrafast femtosecond optical pulses with narrow pulse width and high peak power are widely used in many scenarios such as high-precision measurement, material processing, and signal processing. As the main means of generating femtosecond pulses, mode-locking technology relies on polarization control and Kerr nonlinear nonlinear polarization evolution (NPE). Mode-locking has become an important choice for realizing mode-locked lasers because of its simple structure and superior performance. Through fine polarization adjustment, the NPE mode-locked laser can generate various pulse states, but it is very sensitive to the polarization state, and it is difficult to quickly make the laser work in the required pulse state through manual polarization control after startup. In addition, the drift of the polarization state caused by continuous environmental disturbances increases the difficulty of maintaining the operation of the NPE mode-locked laser in the desired pulse state for a long time through manual polarization control. Chirped pulse amplification (CPA) is the core technology to greatly increase the energy of femtosecond pulses. However, the CPA system is complex and has many adjustable parameters. The traditional optimization process is based on manual adjustment, which has a large workload, low efficiency, poor stability and repeatability. After each restart, the time for parameter adjustment and optimization is usually in days. The most important thing is that it is almost impossible to guarantee that the obtained laser output index is the optimal result, and it is difficult to achieve continuous and stable output of optimal pulses.

This research is dedicated to solving the problems of difficulty in starting the femtosecond laser oscillation stage, frequent loss of lock, and difficulty in achieving continuous and stable output of optimal pulses in the femtosecond amplification stage. Propose the intelligent feedback technology route of "intelligent identification + intelligent control", use high-speed ADC sampling, combined with artificial intelligence algorithm to accurately identify the output pulse state of femtosecond oscillation level and femtosecond amplification level; based on the identification results, use intelligent optimization algorithm Control the high-speed DAC to drive the relevant actuators in the femtosecond oscillation stage and femtosecond amplification stage, so that the laser output can quickly approach the target pulse state. In addition, the intelligent feedback system will continuously monitor the laser output, which can continuously lock the laser output in the target pulse state.