Design Of Mid-infrared High Power Laser Control System

With the continuous development of semiconductor lasers,people's demand for high-power lasers is becoming more and more urgent.After decades of development,high-power semiconductor lasers have made breakthrough progress,and both output power and photoelectric conversion efficiency have been greatly improved.In the mid-infrared field,quantum cascade lasers have become one of the major sources of mid-infrared high-power lasers due to their advantages.With the development of high-power lasers,people have further requirements on the output power and performance parameters of the drive control system of high-power and high-performance lasers.How to design a control system with superior performance is of great significance for high-power mid-infrared lasers.First,the basic situation of high-power semiconductor lasers(including quantum cascade lasers)is introduced,and the research status of high-power mid-infrared lasers at home and abroad is introduced.Then according to the specific requirements of the laser drive,the overall design of the mid-infrared high-power laser control system was proposed.Secondly,the theoretical analysis of the working model of the control system is introduced.Through the theoretical analysis of the quantum cascade laser model and the TEC temperature control model,the performance of the laser in the continuous and intermittent operation modes is compared,and the final laser system is determined.The work programme includes the number of lasers selected,the use of intermittent operation,and the three-level TEC cascade temperature control program.Thirdly,the hardware design and software design of mid-infrared high power control system are introduced in detail.Among them,the hardware part mainly includes MCU control system,power supply system,laser drive system,TEC temperature control drive system,signal acquisition system and communication system.According to the power supply requirements,the power supply system has designed a corresponding protection circuit.The laser drive system generates PWM waves with adjustable frequency and duty cycle,and adjusts the amplitude of the PWM pulse to control the operating current of the laser.The two are superimposed to generate the operating current for driving the laser.The TEC temperature control drive system adopts the way of controlling the MOS switch to realize the cooling or heating of the TEC.The signal acquisition system collects the working status of each part of the system and the temperature value of the system and the light intensity of the laser light emission in real time to ensure that each part works normally.The software part mainly includes main program design,laser driver program design,TEC driver program design,A/D collection program design and communication program design.In this paper,the specific programming scheme and program flow chart are given for the functions to be realized in each part of the software.Finally,the hardware circuit debugging and software debugging of the laser drive system are performed.According to the problems in the debugging process,a further improvement scheme is proposed.