Research And Design Of The Engineering Control System For All-solid-state Lasers

All-solid-state laser, which is widely used in recent years for its advantages of highefficiency, long longevity, compacting structure, good beam quality, has broad marketprospects. However, all-solid-state laser is very sensitive to drive current and temperature;therefore we need controller with high performance. Control system is an important part ofthe laser equipment, also is a key technology for the domestic made laser equipment to beon the way to industrialization.On the basis of analyzing of LD power supply and thermal control of crystals, asolution for all-solid-state laser control system based on DSP (TMS320F28335) wasproposed, realized the current and temperature control of the pump source LD and it’sprotection, the constant temperature control of the frequency doubling crystal and thefrequency mixing crystal, the generation and control of frequency signal for Q-Switch andthe interface function. This system used the constant current source controlled by MOSFET,temperature control circuit and the protection circuit as LD power supply, used a bridgecircuit based on platinum resistances, instrumentation amplifier IN114and A/D converterwith16resolutions as high precision temperature measure circuit. The driving chipMAX1968drove the Thermoelectric Cooler, realized the temperature control of thefrequency doubling crystal and the frequency mixing crystal. The algorithm ofsegment-PID was adopted to improve the control stability and speed.The performances of this system have been measured as follows: the LD current isadjustable in range0to9A, the LD temperature is adjustable in range15to35℃, theripple of LD current less than0.01A and the ripple of LD temperature less than±0.1℃under the condition of continue working for12hours; The temperature of frequencydoubling crystal and the frequency mixing crystal is adjustable in range40to50℃, withstability of±0.006℃under the condition of continue working for12hours, the temperaturecan reach steady within3minutes; The frequency of Q-Switch signal is adjustable in range 20to200KHz, duty ratio is adjustable in range5%to95%, with internal and externaltrigger mode optional; capable of display, keyboard, storage, communication with PC. Theresults show that the system has strong stability and high adjusting speed of current andtemperature. The prototype of the laser can output high quality laser-beam in a long periodof time with stable status. It provides great significance and practical engineering value forthe industrialization of domestic made all-solid-state laser.