高功率密度脉冲激光的光纤耦合性能一直制约着激光飞片起爆技术的工程化应用。针对106 W/cm2级功率密度脉冲激光在光纤中的耦合特性, 设计了一套光纤对准夹具, 用于开放光路下脉冲激光的光纤耦合。使用波长为1 064 nm, 脉宽6 ns的调Q脉冲Nd:YAG激光, 研究了其在大功率石英光纤和AgI/Ag空芯光纤中的能量传输效率和损伤阈值。结果显示: 在焦点前后10 mm范围内, 石英光纤的传输效率平均值为76.2%, AgI/Ag空芯光纤的传输效率平均值为61.8%; 在焦点前2 mm处, 测得石英光纤损伤阈值为22.3 mJ, AgI/Ag空芯光纤损伤阈值为29.4 mJ。通过对比结果可知, AgI/Ag空芯光纤拥有较高的损伤阈值, 然而AgI/Ag空芯光纤的传输效率比石英光纤低约15%, 其工程化应用潜力还有待进一步开发。

Power delivery characteristics of fibers for high power density pulse laser makes it difficult to apply laser-driven miniflyer system into practice. In order to investigate the power delivery characteristics of fibers, an optical fiber fixture was designed in the experimental set up, which was useful to alignment of the laser beam. The transmission efficiency and damage threshold of high-peak power density laser pulses with width of 6ns and wavelength of 1 064 nm via both silica fiber and AgI/Ag hollow fibers with core diameter of 600 μm are demonstrated. It is found that, within 10 mm from the focal, the average transmission efficiency of the silica fiber is 76.2%, which were 61.8% of the hollow fiber. 2 mm before the focal, the damage threshold of silica fiber and AgI/Ag hollow fiber are 22.3 mJ and 29.4 mJ. By comparing the results that, AgI/Ag hollow fiber has a higher damage threshold, its transmission efficiency is about 15% lower than the silica fiber, its engineering potential still needs to be further developed.