A Hybrid Amplified Nanosecond Pulsed Laser Based on Cascaded SOA Modulation

To address the requirements of spatial laser applications for pulse laser sources in terms of temporal flexibility, frequency stability, and system compactness, this paper reports a nanosecond pulsed laser based on a semiconductor-fiber-solid-state hybrid architecture for master oscillator power amplifier (MOPA) operation. Using a 1064 nm distributed feedback (DFB) single-frequency continuous-wave laser as the seed source, a two-stage semiconductor optical amplifier (SOA) is employed to achieve high-extinction-ratio pulse chopping and custom time-domain modulation. By designing the SOA drive current waveform, gain saturation and pulse distortion during the subsequent high-gain amplification process are actively pre-compensated, thereby enhancing the temporal fidelity and consistency of the amplified pulses. At a repetition rate of 1 kHz, ultra-Gaussian pulses with a pulse width of 40 ns were generated via SOA current modulation. After two-stage single-pass fiber amplification, the single-pulse energy of the seed light was increased to 2.1 μJ, with a spectral contrast exceeding 35 dB; Subsequently, energy is further boosted by a two-stage Nd:YVO₄ slab preamplifier and a two-stage Innoslab main amplifier composed of Nd:YVO₄ and Nd:YAG slabs, respectively, ultimately yielding a laser output with a single-pulse energy of 18.5 mJ and a pulse width of 10.6 ns, with a spectral linewidth of approximately 0.03 nm, with a spectral contrast exceeding 30 dB.This study achieves high-energy output while offering high flexibility in controlling pulse width, time-domain waveforms, and repetition rates. The resulting high-energy, high-contrast tunable pulses can serve as an excellent fundamental-frequency source for nonlinear frequency conversion, demonstrating promising prospects for applications such as spatial hyperspectral detection.