【作者】 解灵运；

【导师】 谢世钟；

【作者基本信息】 清华大学 ， 电子科学与技术， 2004， 硕士

【摘要】 光子晶体是一种介电常数成周期分布的介质材料,周期为光波长量级。在光子晶体材料中存在着特殊的频带,在这些频带中光波被禁止传播。如果在光子晶体中引入缺陷,则在禁带中会存在缺陷态,使得与该缺陷态相对应的波长的光子在其中可以存在和传播,利用这种特性可以设计出微米-毫米量级尺寸的光波导器件,具有很多传统波导所无法比拟的优点。本论文从光子带隙理论和制作工艺两个方面对基于SOI、带隙中心位于1550nm的光子晶体带隙材料及光子晶体波导器件进行了深入的研究。理论上采用平面波展开法(PWE)和基于完美匹配层(PML)边界条件的时域有限差分法(FDTD)相结合的技术,对二维光子晶体平板波导的带隙结构及光波传输进行了仿真,设计了多种适合于0.18m标准硅工艺的光子晶体波导器件,包括直线形波导、60°弯折波导、90°弯折波导、T形波导、Y形波导、光子谐振腔、Mach-Zehnder形波导等数种光子晶体波导结构。并对结构参数进行了优化,得到较好的传输结果。此外还将快速傅立叶变换法和Pade近似法相结合给出了谐振腔的品质因数Q的计算方法,通过品质因数研究了波长上下复用器件的设计。在理论设计的基础上,对工艺制作进行了深入的摸索。通过深紫外(DUV)曝光法和电子束(EB)曝光法分别对SOI进行曝光处理,并通过化学辅助离子束刻蚀(CAIBE)技术和电感耦合等离子体刻蚀(ICP)技术刻蚀了硅和SOI晶片,得到二维光子晶体平板波导样品。对该工艺过程各步骤进行了详细的研究,探询适合光子晶体波导的制作条件。利用扫描电子显微镜和原子力显微镜观察样品,对样品的细微结构进行了全面的分析,给出了样品的三维图片。初步搭建测试系统进行测试研究,并腐蚀制作了耦合信号光使用的光纤透镜。本论文对基于SOI的二维光子晶体平板波导在理论和工艺两方面做了开创性的探索研究,为后续光子晶体集成系统的研究打下良好的基础。更多还原

【Abstract】 Photonic crystals (PhC) are optical structures with wavelength-scale periodic variations of the refractive index. There are frequency bands, which called photonic bandgap (PBG), in the periodic dielectric materials. Light with frequency in the PBG can’t propagate through the photonic crystals. If there are defects (dot or line) in the periodic dielectric it will appear frequency bands in which light can propagate. With PhC some waveguides of micrometer-scale can be made which has more advantages than conventional waveguides.In this work PBG structures and PhC waveguides based on SOI (silicon on insulator) are studied from the perspectives of theory and fabrication.A method, which incorporates Plane Wave Expansion (PWE) method with Finite-Difference Time-Domain (FDTD) method, is presented to design and simulate PBG structures and PhC waveguides. This enlarges the scale of simulation and improves the precision and speed of simulation. PWE will present a band structure and according to the band structure, FDTD with a perfectly matched layer (PML) boundary condition gives a light propagation simulation. Some waveguides are designed including line waveguide, 60°bend waveguide, right-angle bend waveguide, T-junction, Y-junction, resonant cavity, coupled cavity waveguide, Mach-Zehnder circuit, etc. FFT and Pade approximation are used to calculate Q-factor. Optimization is done on photonic structures, refractive indices, pitches, diameters of holes, and details of corners. To fabricate PhC waveguide two methods are studied. One is using 248nm deep UV (DUV) lithography and chemically assisted ion-beam etching; the other is electron-beam (EB) lithography and inductively coupled plasma (ICP) etching. The samples of waveguides have been got and which are observed through scanning electron microscope (SEM) and atomic force microscope (AFM). To get appropriate <WP=5>manufacture conditions the micro structures of samples are analyzed and the graphs of samples are given. The setup of measurement is studied and the fiber-lens for coupling input signal light is eroded.This work about PhC based on SOI from the perspectives of theory and fabrication has built a solid foundation for next research on two-dimensional PhC waveguides.更多还原