Research And Implementation Of Key Technologies Of Semiconductor Laser Control System

At present,COVID-19 is rampant,and the public is increasingly concerned about PCR(polymerase chain reaction)detection.It is of practical application value to design and develop a high-precision and high-stability semiconductor laser suitable for fluorescent PCR detection.Through the analysis of previous studies,it is found that the current research on semiconductor laser control system is mostly focused on the current or temperature in the control process,and there are some gaps in the research on the key technologies of low-power semiconductor laser control system,such as low accuracy of power output control and unclear stability.The stability of temperature and the stability of output power are the two key technical indicators for the stable operation of semiconductor lasers.Therefore,based on the analysis of the working principle of semiconductors and combined with engineering applications,the key control technologies and scheme design related to semiconductor lasers are studied in this paper,and the following two tasks are completed.(1)The analysis and modeling of semiconductor laser constant temperature control subsystem and the technical scheme design and implementation of the control system.The main design contents of this work include: The analysis of TEC temperature control principle,the design of temperature sampling circuit,ADC data processing principle,the simulation test of PID constant temperature control parameters and the design and implementation of the whole temperature control subsystem.The experimental data analysis results show that the temperature control subsystem meets the design requirements,the working temperature of the laser is maintained at 25? within 120 minutes,the temperature fluctuation is not more than 0.1?,and the temperature stability is 0.76%.(2)The analysis and modeling of the automatic power control subsystem of the semiconductor laser,and the design and implementation of the technical scheme.The specific work contents include: The feasibility of PLT5-488 laser diode power control is analyzed in theory,and the design of constant current source circuit and feedback light intensity detection and amplification circuit is verified by simulation.Based on the above analysis and demonstration,the software and hardware design scheme of automatic power control subsystem is discussed in detail.The measured data show that the performance of the designed power control subsystem meets the design requirements,The injection laser driving current is45 m A,and the current fluctuation is less than 0.34 m A.the stability of the driving current is 0.79%,and the stable output power of the semiconductor laser is 20 m W within 120 minutes when the working current is set to be 45 m A.the fluctuation range is less than 0.1m W,and the output stability is 0.85%.The output optical power can be adjusted within a certain range,the average power output stability is 0.89% from 15 m W to 20 m W.To sum up,the temperature and power control system of semiconductor laser designed in this paper completely meets the design requirements,The stability of temperature and output power is better than1%.Compared with some common products on the domestic market at present,it has certain advantages in the stability of temperature control,the stability of output optical power and the cost of price.Compared with some products of advanced foreign companies,it also has price advantages.The method can provide a first-step guarantee for the accuracy of the PCR detection result,and can also provide technical support for the application control of the low-power semiconductor laser in other fields because the output light power can be adjusted within a certain range.