硅基亚波长偏振无关光栅耦合器及分束器的研究

发布时间：2018-06-24 08:22

本文选题：硅基光电子 + 光栅耦合器　；参考：《国防科学技术大学》2015年硕士论文

【摘要】：光栅作为一种重要的光学元件,在漫长的历史长河中被不断的探索。二十世纪五十年光栅技术开始蓬勃发展,至今工艺已经十分成熟。随着信息技术的不断发展,硅基光子学研究的不断深入,硅基光栅耦合器以其工艺简单,易对准,对准容差大,无需划片,便于集成的优势得到了广泛的关注。本文根据平面波导的导模原理,在分析光栅耦合的位矢条件和光在波导中的偏振特性的基础上,利用等效介质模法和有限时域差(FDTD)分计算方法,对偏振无关光栅耦合器,紫外光栅耦合器,以及基于silicon-on-sapphire材料的波长为2.78)的光栅耦合器进行了研究。本文的理论工作如下:(1)设计了一种偏振无关光栅耦合器。传统偏振无关光栅耦合器讨论的都是TE波和TM波的基模,通过设计复杂的结构来实现偏振无关的设计。本文中,则讨论TE波的基模TE0和TM波的一阶模TM1,设计出了结构更简单的偏振无关光栅耦合器,并且取得的效果更好。这种偏振无关耦合器可以实现TE波和TM波的同时耦合。当为1.56μm时,TE波和TM波的耦合效率相等,并且超过60%。TE波和TM的耦合能量最高分别是72%和75.15%,1dB带宽分别为30nm和40nm,耦合能量峰值所对应的波长之间的差异大约有35nm。(2)设计了一种偏振无关的光栅分束器。这种光栅分束器是基于布拉格衍射条件和位相匹配方程设计的。有限时域差分法(FDTD)方法模拟结果显示,当光通过光栅分束器后,向两不同方向的波导中分束,两方向所分的能量几乎相等。TE波耦合进右边波导和左边波导中的耦合效率分别是42.54%和43.68%。TM波为46.03%和44.07%。该光栅分束器采用周期性结构设计,最小线宽为360nm,工艺上可以实现,也是现在所有同类型设计中最简单的结构。(3)设计了一种紫外波段的光栅耦合器,可以使波长为300nm的紫外光,通过光栅耦合进SiO2波导中,耦合效率超过60%;在波长为296nm时,耦合效率可达88.5%。经理论分析和数值模拟,最终得到光栅周期为0.28μm,光栅脊宽154nm,1dB带宽为5nm,这种设计可以很好的应用于片上光谱仪的研究。(4)在硅基蓝宝石上设计一种光栅适用于2.7μm波长的光耦合进波导,耦合效率可达75%,通过引入反射光栅布拉格反射层使耦合效率提高到80%以上。主要可用于片上光谱仪的研究
[Abstract]:As an important optical element, grating has been continuously explored in the long history. Grating technology began to flourish in 50 years of the twentieth century, and the technology has been very mature. With the development of information technology and the development of silicon-based photonics, the advantages of silicon based grating couplers, such as simple process, easy alignment, large alignment tolerance, no need for slicing and easy integration, have been paid more and more attention. According to the guiding mode principle of planar waveguide, on the basis of analyzing the position vector condition of grating coupling and the polarization characteristic of the light in the waveguide, the polarization independent grating coupler is calculated by using the equivalent dielectric mode method and the finite time domain difference (FDTD) method. The UV grating coupler and the grating coupler with wavelength of 2.78 based on silicon-on-sapphire are studied. The theoretical work of this paper is as follows: (1) A polarization-independent grating coupler is designed. The traditional polarization-independent grating couplers all discuss the fundamental modes of te and TM waves. The polarization-independent design is realized by designing complex structures. In this paper, the fundamental mode TE0 of te wave and the first order mode TM1 of TM wave are discussed, and the polarization independent grating coupler with simpler structure is designed, and the effect is better. The polarization independent coupler can realize simultaneous coupling of te wave and TM wave. At 1.56 渭 m, the coupling efficiency of te wave and TM wave is equal. And the coupling energy of above 60.te wave and TM is 72% and 75.15dB bandwidth is 30nm and 40nm, respectively. The difference between the wavelength corresponding to the coupling energy peak is about 35nm. (2) A polarization-independent grating beam splitter is designed. The grating beam splitter is designed based on Bragg diffraction condition and phase matching equation. The simulation results of the finite-time-domain difference method (FDTD) show that when the light passes through the grating splitter, it splits the beam into two waveguides in different directions. The coupling efficiency of te wave coupled to the right waveguide and the left waveguide is 42.54% and 43.68% respectively, and the coupling efficiency of TM wave is 46.03% and 44.07% respectively. The grating splitter is designed with periodic structure, the minimum linewidth is 360 nm, which can be realized in technology and is the simplest structure of all the same type designs. (3) A grating coupler in ultraviolet band is designed, which can make the wavelength of 300nm ultraviolet light. When the grating is coupled into the Sio _ 2 waveguide, the coupling efficiency is over 60 and the coupling efficiency can reach 88.5when the wavelength is 296nm. Through theoretical analysis and numerical simulation, Finally, the grating period is 0.28 渭 m, and the grating ridge width is 154nm-1 dB bandwidth is 5 nm. This design can be applied to the study of on-chip spectrometer. (4) A grating coupled waveguide with 2.7 渭 m wavelength is designed on Si-based sapphire. The coupling efficiency can reach 75%, and the coupling efficiency can be increased to more than 80% by introducing reflection grating Bragg reflectance layer. It can be used in the study of on-chip spectrometer.
【学位授予单位】：国防科学技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN256;TN622

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