High-peak-power MOPA-based narrow-linewidth nanosecond pulsed fiber lasers in 2μm band

We propose a 1950nm high average power, large pulse energy narrow-linewidth nanosecond pulse fiber laser. A closed-loop temperature control technique is employed in the design of the seed laser driving circuit system to ensure high power, high wavelength stability, and ultra-low noise characteristics. The acousto-optic modulator (AOM) is used to modulate the pulse of a continuous seed laser, and the rise time of the output pulse can be controlled to obtain the desired pulse shape and width. A master oscillating power amplifier (MOPA) structure is adopted to amplify the modulated power of the laser. Amplified by cascade amplification technique, the average output power of the pulse with the output pulse train has a repetition rate of 10MHz is 3.5W and the pulse width is 300ns, corresponding to a peak power of 1.17kW and a pulse energy of 350μJ. This type of fiber laser has vast possibilities of application especially in lidar and high-precision measurement.