光耦合器的模拟及设计和光波导器件的制作工艺研究

【作者】 王莉蓉；

【导师】 何赛灵；

【作者基本信息】 浙江大学 ， 光学工程， 2003， 硕士

【摘要】 在两年半的硕士学习期间，我将光通信器件的模拟与设计和光波导器件的制作工艺研究作为自己的研究方向。本论文总结了我两年来的研究成果。它分为理论设计和实验两个部分。 第一部分是光耦合器的模拟与设计。光耦合器是光网络中的重要器件，在WDM系统中，光耦合器几乎无所不在。本论文对各种平面波导型耦合器：MMI、分支波导、定向耦合器和Mach-Zehnder进行了模拟和优化设计。首先建立了光束传播法（BPM）的模拟平台，解决了边界问题。利用建立的三维BPM平台设计了渐变折射率波导的MMI耦合器。在设计Y分支波导结构时，考虑常规工艺误差的影响，引入多模波导作为Y分支波导结构的过渡区，利用参数空间搜索法来设计结构参数，实现低损耗的Y分支结构。运用超模解方法，比较了定向耦合器计算模型（二维模型和三维模型）对计算结果的影响，指出由于等效折射率法的精度问题，应用二维计算模型设计结果与实际器件的性能指标有着较大的差别，因此定向耦合器的设计应选用三维计算模型。实际的设计过程中，考虑到定向耦合器输入波导和输出波导部分的耦合影响，围绕耦合模理论计算结果手动调节耦合区长度，并应用三维BPM来模拟设计，得到耦合区长度，设计了精确的3dB定向耦合器。为了设计对波长不敏感的SOI材料的MZ功分器，利用束传播法（BPM）和有限差分模式解方法（FDM）对Mach-Zehnder结构的组成部分定向耦合器和相位延迟部分做了波长相关特性的计算，然后通过遗传算法优化设计了Mach-Zehnder的结构参数。计算得到的波长特性曲线表明该SOI功分器波长平坦而且偏振相关性小。此外，提出了用遗传算法来优化设计SiO₂掩埋型波导材料的MZ波长平坦功分器的上层结构参数。 第二部分是对光波导器件制作工艺的研究。工艺掌握的成熟程度直接关系到能否制作出合格的平面波导器件，从而实现理论设计的结果。本论文中具体研究的工艺内容有：光刻的工艺参数研究；剥离法光刻工艺的研究；用溶胶凝胶法制备二氧化硅膜；Na⁺-K⁺离子交换玻璃波导的制作。探讨了以上工艺的实验原理，给出了实验结果，并对各种实验结果进行了定量或定性的分析。更多还原

【Abstract】 In two and half years’ graduate study,I focused my efforts on simulation and design for optical communication devices and study of fabrication technologies for optical waveguide devices. 1 summarized my main research results and wrote this thesis.The first part of this thesis is for simulation and design of planar waveguide optical couplers. Optical couplers play fundamental roles in passive optical distribution networks and complex photonics integrated circuits. In this thesis,optical couplers consisting of multimode interference (MM!) coupler,Y branch,directional coupler(DC) and Mach Zehnder interferometer(MZI) were analyzed and simulated. First,I made and improved some Beam Propagation Method (BPM) programs,consisting of 2D(EIM-BPM) and 3D BPM,with transparent boundary condition(TBC) and perfectly matched layer(PML) boundary condition respectively. Applying an exact modal propagation analysis method and self-imaging theory,I analyzed the principle of MMI coupler. Then,the self-imaging effect in graded-index waveguide has been analyzed and simulated using three-dimensional BPM. Considering normal technology error,a low loss Y-branch structure (symmetric or asymmetric) with a multimode waveguide transition section is introduced and designed. A wide range of the branching ratio can also be achieved for the asymmetric case. Using supermode theory,I compared the design results of directional coupler by means of 2D mode and 3D mode and designed 3dB directional coupler using 3D BPM and couple mode theory. In order to design wavelength insensitive power splitter based on SOI,the wavelength characteristic of Mach-Zehnder interferometer were investigated by means of BPM and FDM (finite-difference method). Then the parameters of Mach-Zehnder interferometer were optimum designed using genetic algorithm. Besides,genetic algorithm is also used to optimize the upper tier parameters of MZI based silica-on-silicon to attain a flat spectral response.The second part of this thesis is for the study of fabrication technologies of optical waveguide devices. The technologies I explored consist of photolithography technology,Lift-off lithography process,technology of growing silicon dioxide films using Sol-Gel coating technique,and fabrication of Na+-K+ ion-exchanged glass waveguide. In this thesis,the experiment principles were investigated and the experimental results were given and discussed更多还原