Development Of Driving Power Supply For Acoustic Light Modulator Of Pulsed Fiber

With the development of laser technology, pulsed fiber laser is widely used in the field of small and medium-sized power laser processing for its excellent capability. By utilizing acousto-optic modulation, it is quick and efficient to control pulse repetition frequency and peak power. So the special needs of laser process are fulfilled greatly. Acousto-optic modulator driving power is the key part of pulsed fiber laser. Therefore, how to improve the circuits’ performance is a key factor that decides the output of laser quality. Thus it has broad space for development and great application value to do the research on acousto-optic modulator driving power.The thesis is mainly about the research on Acousto-optic modulation technology of MOPA fiber laser, which proposes a solution with lower power consumption and adjustable-output with stability to meet the technological requirements of fiber acousto-optic modulator according to its characteristics. By controlling the RF power output with 2ASK modulation, which controls the time and repetition frequency of acousto-optic modulator, we successfully work out the non-linear distortion of output waveform and inefficiency of power amplifier circuit by adapting two-stage power amplifier mixing A and C circuits.In the power debugging process, the overheated MOSFET became the hard part of the project. The thesis had analyzed the reasons of overheating and given the effect solution by actual debugging. The experimental results are as follows: acousto-optic modulator driving power in the project has excellent abilities of 2W output of RF power, repetition rate from 20 k Hz to 200 KHz and 10 ns of switching time(one RF driver oscillation period). And the diffraction efficiency of F-QSG100-1optical fiber type acousto-optic modulator was up to 87.22%. After mixing the system above with fiber laser of MOPA structure, the laser pulse width was 100 ns while the modulation signal works with frequency for 20 k Hz and pulse width for 400 ns.The test results showed that the acousto-optic modulator drive in the experiment met the technical requirements of the pulsed laser system which not only reduced the response time of drive switch, but also greatly improved the efficiency of the power output stage. It provides a modulator drive with stable performance for MOPA fiber laser which currently dominates the laser marking industry.