高功率脉冲(10 MW)激光光纤偏振走离复合放大技术

We present a fiber pulse polarization division combing amplification technique to break through the limitation on the maximum pulse peak power set by fiber nonlinear effects, e.g., self-focus, Stimulated Raman and Brillouin Scattering, self-phase-modulation. We study the theory and experiment of the fiber pulse laser at 10 MW high peak power output. Firstly, an analytic model is developed to design the high birefringence hollow core photonic bandgap fiber structure and evaluate its mode distribution and transmission. We build the physical mode of the fiber transmission and amplification progress of the fiber polarization division combining pulse trains at 10-ps order short pulse spacing. We achieve the influence rule of the fiber parameters, pump parameters and nonlinear effects of the mode dispersion, spectrum dispersion, pulse shape distortion and mode distortion. We do research the key elements of system, including low loss polarization division combining fiber series, high power hollow core fiber circulator, large mode field fiber Faraday rotator mirror and pump combiner. Finally, a peak power of greater than 10 MW and over the silica fiber self focus limitation with a diffracted limitation beam quality, ~10ps pulse duration, wavelength of 1.03μm, 50 kHz repetition rate will be developed experimentallly.4

提出光纤偏振走离复合放大技术，以突破脉冲光纤激光所受到的自聚焦、受激 拉曼、布里渊散射、自相位调制等材料非线性效应对高峰值功率的瓶颈限制，展开10MW 级 皮秒脉冲高峰值功率脉冲光纤激光的理论和实验研究。首先研究高双折射空芯光子带隙光纤 结构与模式特性，建立适合高功率10ps 级短时间间隔的偏振分离脉冲序列在空芯光纤、大 模场光纤传输与放大过程的物理模型，从而能够探求模式色散、光谱色散、波形畸变、模式 畸变等激光输出特性在不同光纤参数、泵浦参数、以及非线性效应等条件下的理论规律；结 合理论研究结果设计实验方案，研制出低损耗光纤偏振走离复合光纤系列，与高功率空芯光 纤环形器、大模场法拉第旋转镜、大模场泵浦合束器等新型器件，拟获得波长1.03μm，脉 宽约10ps，脉冲重复频率50kHz，超过石英光纤自聚焦阈值的10MW 脉冲峰值功率、近衍射 极限光束质量的光纤激光输出。

提出光纤复合放大技术，以突破脉冲光纤激光所受到的自聚焦、受激拉曼、布里渊散射、自相位调制等材料非线性效应对高峰值功率的瓶颈限制，展开10MW 级皮秒脉冲高峰值功率脉冲光纤激光的理论和实验研究。首先研究ACCC光纤结构与模式特性，建立适合高功率放大的光纤传输与放大过程的物理模型，从而能够探求模式色散、光谱色散、波形畸变、模式畸变等激光输出特性在不同光纤参数、泵浦参数、以及非线性效应等条件下的理论规律；结合理论研究结果设计实验方案，研制出全光纤锁模超快激光，有效抑制非线性效应，有效放大，波长1.03μm，脉宽20ps，可压缩至200fs，10MW 脉冲峰值功率、近衍射极限光束质量的光纤激光输出。