光纤耦合LD光束特性及其对振荡光模式的影响

基于菲涅耳-基尔霍夫衍射积分理论,研究了端面泵浦固体激光器中泵浦源——LD阵列光纤耦合模块的输出光空间特性,及其对振荡光特性的影响。结果显示:LD阵列光纤耦合模块的输出光强分布不平滑,呈多尖峰分布,尖峰位置对LD光束指向角敏感,随指向角、空间排布等因素的变化而变化,是多种因素综合作用的结果;具有尖峰结构的泵浦光场对振荡光横模结构有直接影响,泵浦光尖峰位置越居中,光强径向分布曲线在轴心处越凸起,振荡光光束质量越好,越凹陷,振荡光光束质量越差,在激光器设计中应有针对性地具体考虑应对措施。

Output beam properties of fiber-coupled LD array and their impacts on oscillating light

Based on Fresnel-Kirchhoff diffraction integral theory, output beam properties of fiber-coupled LD array and their impacts on oscillating light are examined. The results show that deviating from Gaussian distribution, the output light intensity on the exit surface of the optical fiber is in multi-peak distribution. Positions of peaks are sensitive to LD beam directions, and will change with the variation of LD beam directional angle and spatial location. This phenomenon is a result of various factors. Pump light with multi-peak distribution has a direct impact on the mode structure of the oscillating light. The more pump light intensity peaks concentrate in center, and the more convex of the light intensity is, the better oscillating light beam quality will be, which should be considered in laser-diode pumped solid-state lasers design.