报道了利用多模光纤作为相位共轭镜应用于重复频率100 Hz,脉宽20 ns的电光调Q四通放大LD抽运激光器的实验研究。由于光纤受激布里渊散射(SBS)存在的阈值效应,可以抑止使用平面全反镜的四通放大系统中难以克服的放大级自振荡(SO)和放大自发辐射(ASE)效应,以获得高能量高光束质量的激光输出。实验中在20 ns,100 Hz和注入光纤能量4.6 mJ的情况下获得了4.1 mJ的1064 nm的基模激光输出。激光光束模式接近TEM00模,且脉宽被压缩至4.7 ns。在使用了光纤相位共轭镜的四通放大技术后,很好地补偿了由板条放大器热效应造成的光斑畸变。输出光斑很好地复原了振荡级输出光斑的光强空间分布。

Using a 200 μm-core multimode optical fiber as the phase conjugator mirror, an LD-pumped Q-switched four-pass MOPA system operated on 100 Hz repetition rate and 20 ns pulse width has been experimental investigated in this paper. As a result, high quality laser beam with energy of 4.1 mJ and energy-stability less than 10% have been obtained when 4.6 mJ pump energy injected into fiber phase conjugator. The self-oscillating (SO) in amplifier and amplified spontaneous emission (ASE) has been validly suppressed. In additional, the pulse width of laser has been compressed to 4.7 ns. Due to the using of fiber phase conjugating mirror, the deformation formed by the thermal effect from the slab amplifier has been compensated after four passing. The output beam profile resumes the intensity distribution of the oscillator output beam.