基于激光直写的光纤微透镜与激光二极管耦合的研究

发布时间：2018-03-14 07:47

本文选题：激光直写　切入点：光纤微透镜　出处：《浙江大学》2015年硕士论文　论文类型：学位论文

【摘要】：激光二极管具有体积小、重量轻、价格便宜等优势,在光纤通信、生物医学、激光泵浦、材料加工等领域被广泛应用。在许多应用场合都需要将激光二极管与光纤进行耦合,然而激光二极管由于其发光面较宽,其出射光束为椭圆形模场,这与光纤的圆形模场不匹配,因此两者直接的耦合效率很低。为了提高激光二极管与光纤的耦合效率,一种常用的方法是在光纤端面上制作微透镜,与激光二极管直接耦合。尽管目前已有如熔融拉伸法、化学蚀刻法、研磨抛光法等一些制作光纤微透镜的方法,但这些方法或多或少存在着制作过程复杂,耗费时间长,加工成本高等缺点。因此本文提出激光直写法制作光纤微透镜,该方法能够直接在光纤端面上打印出微透镜,操作过程简单方便、快速、成本低、可重复性高。本文采用激光直写法制作出不同形状的光纤微透镜,并对它们的耦合效率进行了测试。测试采用650nm波长的激光二极管,其水平发散角为6.50,垂直发散角为35°,椭圆光束的长宽比为5。用该激光二极管与制作的光纤微透镜进行耦合,测试耦合效率,实验中获得的最高耦合效率为53.5%。耦合效率与光纤微透镜的形状有关。将光纤微透镜尖端的曲率半径定义为其最小内切圆的半径,当内切圆的半径为8.1μm时,具有最高的耦合效率。光纤微透镜的高度与其曲率半径成反比,耦合效率最高时,光纤微透镜的高度为50μm,容差为+5/-0μm。将光纤微透镜顶点与激光二极管发光面之间的距离定义为光纤微透镜的工作距离,则耦合效率与工作距离有关。实验中获得,当工作距离为15.8μm时,耦合效率最高。光纤微透镜与激光二极管存在轴向位移(水平或垂直)、角向倾斜(水平或垂直)时,其耦合效率下降。实验测得,耦合损耗增加1dB,X轴、Y轴两个方向偏移位移的容忍误差分别为±2.5μm、±1.2μm,水平倾斜角和垂直倾斜角的容忍误差分别为±2.0°、±5.0°。本文在ZEMAX软件中采用光线追迹法对光纤微透镜与激光二极管的耦合进行了仿真,仿真结果与实验结果一致。
[Abstract]:Laser diodes are widely used in optical fiber communication, biomedicine, laser pump, material processing and other fields because of their advantages of small size, light weight, low price and so on. However, due to the wide luminescence surface of laser diode, the output beam of laser diode is elliptical mode field, which does not match the circular mode field of optical fiber, so the direct coupling efficiency of both laser diode and fiber is very low, in order to improve the coupling efficiency between laser diode and fiber, One commonly used method is to make microlenses on the end of the fiber, which are directly coupled to laser diodes. Although there are some methods for making optical fiber microlenses, such as melt drawing, chemical etching, grinding and polishing, etc. However, these methods have the disadvantages of complicated fabrication process, long time consumption, high processing cost, etc. In this paper, a laser direct writing method is proposed to fabricate optical fiber microlens, which can print out the microlens directly on the end surface of the optical fiber. The operation process is simple and convenient, fast, low cost and high repeatability. In this paper, optical fiber microlenses with different shapes have been fabricated by laser direct-writing, and their coupling efficiency has been tested. The horizontal divergence angle is 6.50, the vertical divergence angle is 35 掳, and the aspect ratio of the elliptical beam is 5. The coupling efficiency is measured by coupling the laser diode with the fabricated fiber microlens. The maximum coupling efficiency obtained in the experiment is 53.5. The coupling efficiency is related to the shape of the fiber microlens. The radius of curvature at the tip of the optical fiber microlens is defined as the radius of its minimum inner tangent circle. When the radius of the inner tangent circle is 8.1 渭 m, Has the highest coupling efficiency. The height of the optical fiber microlens is inversely proportional to its curvature radius, when the coupling efficiency is highest, The height of the optical fiber microlens is 50 渭 m and the tolerance is 5 / -0 渭 m. If the distance between the top of the fiber microlens and the luminescent surface of the laser diode is defined as the working distance of the optical fiber microlens, the coupling efficiency is related to the working distance. When the working distance is 15.8 渭 m, the coupling efficiency is the highest. When there is axial displacement (horizontal or vertical) between the optical fiber microlens and the laser diode, the coupling efficiency decreases when the angle tilts (horizontal or vertical). The tolerance error of offset displacement of X axis and Y axis is 卤2.5 渭 m and 卤1.2 渭 m respectively, and the tolerance error of horizontal and vertical tilt angle is 卤2.0 掳and 卤5.0 掳respectively. In this paper, the ray tracing method is used to trace the optical fiber microlens and laser in ZEMAX software. The coupling of the diode is simulated. The simulation results are in agreement with the experimental results.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN31

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