High-performance narrow-linewidth nanosecond pulsed fiber laser in 2 μm band

Based on an all-fiber master oscillator power amplifier (MOPA) structure, a 1950-nm narrow-linewidth, single-mode, high peak power nanosecond pulsed fiber laser was developed. The seed source is a distributed feedback (DFB) semiconductor laser with a linewidth of 0.5 MHz. A precise and stable closed-loop temperature control technology is used to design the driving circuit of the seed laser, which ensures the stability of the laser wavelength and power, and greatly reduces the frequency and intensity noise of the laser. The continuous seed laser is modulated by an acousto-optic modulator (AOM). At the same time, the high-frequency control technology of acousto-optic modulator and cascade amplification technology are used to realize the continuous adjustable of laser pulse shape (Gaussian pulse or square wave pulse), repetition rate (1 kHz ~ 300 kHz) and pulse width (50 ns ~ 500 ns) of 2.0 μm band single frequency laser. This laser is very suitable for coherent lidar applications