光纤束耦合LD输出光束的空间耦合技术研究

基于多模大芯径光纤的端面出射光场可视为高斯分布,光纤束耦合LD各纤芯出射的光束互不相干;对光纤束耦合LD输出光束通过空间耦合光学系统后的光强分布进行了数值模拟和实验研究,模拟计算结果和实验结果的规律基本吻合。结果表明,用单个薄凸透镜组成耦合系统时,耦合后的光束在焦平面上中心光强最大,光斑尺寸最小;随着薄透镜焦距的增大,焦平面上的光斑尺寸呈线性增大,而中心光强急剧减小。

Study of space coupling technology of fiber bundle coupling LD output beams

Based on the fact the optical field distribution of the transmitted beams of a multi-mode fiber can be treated as Gaussian distribution,the optical fields of a fiber bundle made up of multi-mode fibers are incoherent.The intensity distribution of a fiber bundle coupling LD output beams transmitting space coupling system is numerically simulated and experimentally studied.The simulation results are in good agreement with the experimental ones.Both of them show that for a thin convex lens,the maximum intensity value and the minimum beam size are obtained in the focal plane,and that with the increase of the focal length,the beam size increase linearly and center intensity decrease dramatically in the focal plane.