【作者】 梁雄；

【导师】 郭福源；

【作者基本信息】 福建师范大学 ， 光学， 2006， 硕士

【摘要】 随着信息社会的到来，人们对信息的需求量与日俱增。平面光波导作为集成光路中重要组成元素，对其参数和性能测量显得尤为重要，测量所得的参数和数据可以为集成光路的制作工艺提供依据和参考，从而提高集成光学系统的工作性能。本论文主要围绕着平面光波导折射率测量方法展开讨论，分析了星形耦合器的总耦合效率。本论文从基尔霍夫衍射积分公式以及平面光波导的模场分布出发，导出了平面光波导的远场衍射表达式，分析了低阶模的衍射特征，并给出了它们的衍射场的相对强度分布曲线图，分析了TE基模的衍射场中央亮条纹光强下降到最大值1／e²随波导归一化频率的变化情况以及TE₁、TE₂、TE₃模极大值对应的空间频率随着归一化频率的变化情况，并用指数函数进行了拟合，拟合的结果跟从衍射表达式数值求解的结果吻合得较好。本文介绍并讨论了高斯光源与光波导之间的耦合、两相邻光波导之间的耦合系数，从空间非接触的两光波导之间耦合效率出发，分析了星形耦合器的耦合效率问题。最后，在传输模近场法的基础上讨论了一种基于远场扫描来测量渐变折射率光波导的方法，分析了衍射场空间角步长和构建波导折射率分布区域之间的关系，讨论和分析了三种有限差分方式的精度问题，重构波导折射率分布应用了利用最小二乘法得到的逆矩阵算法，这种测量折射率分布的方法具有高空间分辨率以及高灵敏度的优点。更多还原

【Abstract】 With information society on the horizon, the information demand is always increasing dramatically. Planar optical waveguides are the base of the integrated optical circuits, and measurement of their parameters and performance is very imperative for improving the performance of devices, because the data from the measure provide a theoretical base and guidance for the fabrication technique of integrated optical circuits in turn. This paper centers on the measurement of refractive index profile of planar waveguide, and in addition, the total coupling of star coupler is analyzed. Firstly, the far-field diffraction equation of planar waveguide’s end-surface is derived from Kirchhoff diffraction integral equation, and its diffractive characteristics are analyzed for the relations between diffraction field and waveguide parameters. Secondly, the coupling efficiency is reviewed and discussed for between the Gaussian beam and planar waveguide, two adjacent planar waveguide and NxN star couplers. Finally, reconstruction of graded refractive index profile of planar wave is presented on the base of inverse matrix algorithm for near-field method, applying discrete Fourier transform and central finite difference method, and herein sampling step of far-field diffraction, inverse Fourier transform and central finite difference method are systematically and detailedly discussed.更多还原