【作者】 刘柳；

【导师】 何赛灵；

【作者基本信息】 浙江大学 ， 光学工程， 2007， 博士

【摘要】 如何减小波导和器件的尺寸是如今集成光学中存在的一个关键问题。由于受到衍射极限的限制，光子学器件很难缩小到波长以下的范围之内。本论文旨在，从理论上和实验上，研究一些亚波长以及纳米尺度下的集成光子学器件，我们讨论了用于减少光子学器件尺寸或者增加其功能性的一些方法，其中包括：基于硅纳米线、光子晶体、表面等离子体的波导及其相关器件。首先，我们详细介绍了一些用于求解麦克斯韦方程组得数值计算方法，包括：时域有限差分法，以及全矢量有限差分模式解。前者可以用来处理光场与介质结构相互作用的问题；后者主要用来求解一个波导结构中的本征模式场分布和传播常数。接下来，我们对加工亚波长或纳米集成光子学器件的工艺方法进行了回顾。这些工艺主要是基于超净室的一些设备，其中主要包括：薄膜沉积、电子束光刻、以及刻蚀。提出了新型的无定形硅SOI结构。分析了各个工艺参数对实际制作结构的影响。我们还介绍了用于测试加工好的光子学器件的端面耦合测试方法。我们在理论上研究了表面等离子体波导及器件。使用表面等离子体波导可以将光场限制在真正意义上的亚波长范围之内。分析了一些相应的非常小型的光子学器件，如：90°弯曲，定向耦合器，共振环滤波器。我们还通过一个实例，即：分支耦合器，验证了使用微波理论来指导设计表面等离子体波器件的可能性，为表面等离子体波器件提供了一个全新的设计途径。我们还分析了金属包层的扫描近场光学探针的一些性质，提出了对于等离子体探针的一种新型激励方式。我们研究了硅纳米线波导以及相关器件。分析制作了具有11nm和1.6nm通道间隔的阵列波导光栅(解)复用器。在该器件中，我们使用重叠型自由传播区的设计，进一步减小了器件的尺寸。我们还设计制作了刻蚀衍射光栅器件。这些基于硅纳米线波导的器件尺寸通常为几百微米左右，比传统的二氧化硅上的相应期间缩小了1—2个数量级。研究了各种二维平板型光子晶体波导。基于一个具有负折射效应的硅柱光子晶体，我们提出了一种新型的光子晶体偏振分束器设计。经测试，该器件的工作波长范围很大，而且在整个范围内的消光比都可达到约15dB。更多还原

【Abstract】 Size reduction is a key issue in the development of contemporary integrated photonics. This thesis is mainly devoted to study some integrated photonic components in sub-wavelength or nanometric scales, both theoretically and experimentally. The possible approaches to reduce the sizes or to increase the functionalities of photonic components are discussed, including waveguides and devices based on silicon nanowires, photonic crystals, surface plasmons, and some near-field plasmonic components.First, some numerical methods, including the finite-difference time-domain method and the full-vectorial finite-difference mode solver, are introduced. The finite-difference time-domain method can be used to investigate the interaction of light fields with virtually arbitrary structures. The full-vectorial finite-difference mode solver is mainly used for calculating the eigenmodes of a waveguide structure.The fabrication and characterization technologies for nano-photonic components are reviewed. The fabrications are mainly based on semiconductor cleanroom facilities, which include thin film deposition, electron beam lithography, and etching. The characterization setup with the end-fire coupling is also described.Surface plasmon waveguides and devices are analyzed theoretically. With surface plasmons the light field can be confined in a true sub-wavelength dimension. Some related photonic devices, e.g., 90° bends, directional couplers, and ring resonators, are studied. We also show that some ideas and principles of microwave devices, e.g., a branch-line coupler, can be borrowed for building corresponding surface plasmon based devices. Metal-coated fiber probes are analyzed and designed. A new scheme of illumination-mode near-field scanning optical microscope has been introduced by employing a plasmon probe with the TM₀₁ mode excitation.Silicon nanowire waveguides and related devices are studied. Arrayed waveguide gratings with 11 nm and 1.6 nm channel spacing are fabricated and characterized. A more compact design with the overlapped free propagation regions has beenemployed for these arrayed waveguide gratings. Etched diffraction gratings are also designed and fabricated. The typical dimension of these devices are several hundred micron, which is 1 — 2 order of magnitude smaller than conventional silica based ones. Various planar photonic crystal waveguides are analyzed and characterized. A compact polarization beam splitter employing positive/negative refraction based on a photonic crystal of silicon pillars is designed and demonstrated. Extinction ratio of ～15 dB is achieved experimentally in a wide wavelength range.更多还原