Design Of Pump Source Driving System For Ultrashort Pulse Laser Based On Embedded System

Not long after the birth of laser technology,scientists have been able to use optical methods to obtain ultra-short laser pulses that the time width of less than the electronic control range of.As researchers continue to make practical achievements in ultrashort pulsed lasers,many related applications are moving out of the laboratory and into processing,measurement,medical treatment,communications,and optical recording.Solid-state lasers and fiber lasers,which produce ultra-shorted pulses of laser,mainly use semiconductor lasers as the pump source,and often r equire multiple beams to be pumped simultaneously.The semiconductor pumped laser is usually excited by the injection current,and the laser power is determined by the difference between the injection current and the threshold current.Due to the heat generated when the semiconductor laser is energized,the threshold current of the laser will change,which leads to the instability of output power and wavelength.Today,due to the reasons of the process,commercial analog power supply can only be applied to the accuracy and stability of the occasion is not high,and high precision digital power supply has large volume,poor flexibility,difficult to integrate,single driving capability and expensive and other shortcomings.Today,due to the reasons of the process,commercial analog power supply can only be applied to the occasion that for accuracy and stability is not high,and the high precision of the digital power supply has a large volume of poor flexibility,difficult to integrate,single drive and expensive and other shortcomings.Researchers generally use two ways to control the temperature :(1)a multi-chip semiconductor cooler is integrated into the driving power supply for temperature control;(2)external optical equipment to stabilize the wavelength of the semiconductor laser to reduce the impact of temperature changes on the semiconductor laser.However,mode one reduces the advantages of semiconductor laser miniaturization and low power consumption,and the external equipment in mode two also has the problem of temperature drift.In order to give full play to the advantages of semiconductor laser in application,we design and implement a driving system for the pump source of ultrashort pulsed laser based on embedded system.The system can provide high precision,high stability and high flexibility of constant temperature control and constant current drive for the five-channel semiconductor laser simultaneously.In order to improve the flexibility and integration of the driving system,the hardware part adopts a modular design scheme which the upper computer,control,driving and power supply are separated.The software part is based on the embedded real-time operating system ?C/OS-III,compared with the traditional front and back system,the program greatly improves the scalability and real-time response of the driving system.The incremental PID algorithm optimized by genetic algorithm is adopted in the current and temperature correction part,which reduces the system overshoot and the time to reach dynamic balance.The driving system has complete protection measures,such as soft start and close,drive circuit detection,over-temperature protection and other functions,to ensure the stable operation of the pump source.In practical application,the output current stability of the driving system is better than 0.001%,and the temperature stability of the semiconductor laser is better than0.035%.The developed drive system is integrated into a 1.5 ?m femtosecond fiber laser to drive the five-channel semiconductor laser pump source.The seed laser,the output laser pulse spectrum,the pulse sequence and the single pulse of the amplifier obtained can all operate stably for a long time.The output power stability of the 1.5 ?m femtosecond fiber laser is 0.16% after three hours of continuous testing.