激光在锥形多模光纤中的耦合效率与传输模式

基于光线追迹的方法建立了典型锥形多模光纤的传输模型，结合激光干扰设备激光的特点，模拟计算了激光在锥形多模光纤中的耦合效率和传输模式，并设计进行了光学实验。仿真和实验结果表明:高斯激光光斑经锥形多模光纤传输后为圆环形光斑；耦合效率随激光入射角的增大而减小，减小的速率随入射角的增大而减小。为解决圆环形光斑分布，提出了将输出端连接的圆柱形光纤弯曲一定角度的方法，该方法可以将光斑改善为二维正态分布的光斑，理论耦合效率近80%。该研究为激光干扰设备的干扰激光直接介入激光制导武器对抗半实物仿真系统提供了理论和实验支持。

Coupling efficiency and transmission mode of laser beam in tapered multimode fiber

Based on ray tracing method, the laser transmission model of typical tapered multimode fiber was established. Integrating the peculiarity of jamming laser beam from the laser jammers, the coupling efficiency and transmission modes of laser spot throughout the tapered multimode fiber were calculated. Experiments were designed and conducted to verify the simulation. The results indicate that the output laser spot behaves circular when a laser spot with Gauss distribution incidences the tapered multimode fiber; the coupling efficiency decreases when the incident angle increases, and the decrement rate decreases as the incident angle increases. In order to solve the circular laser spot distribution, a new method of a small angle bending of the connected cylindrical fiber was introduced, and the output laser spot was improved to two-dimensional normal distribution, the theoretical coupling efficiency was about 80%. This provides a theoretical and experimental support for jamming laser intervening into the laser guided weapon countermeasure hardware-in-loop system.