【作者】 申冰；

【导师】 任晓敏；

【作者基本信息】 北京邮电大学 ， 通信与信息系统， 2013， 硕士

【摘要】 近些年来,微环滤波器由于其具有窄线宽、结构紧凑和易于大规模集成等优势而得到广泛的关注。但传统的基于电介质的微环滤波器的器件尺寸在达到单个波长量级时便不能继续降低,这极大地束缚了光子集成芯片的集成度。为了突破这个极限尺寸的限制,人们便考虑用表面等离子体波导来实现微环滤波器。这是由于表面等离子体波导能对光紧紧地束缚在波导表面,实现光的亚波长传输,因而达到降低器件尺寸的目的。本文对传统的基于电介质的微环滤波器和基于表面等离子波导的微环滤波器均进行了深入的理论研究和实验探索。以下为本文的创新和硕士期间的主要研究工作：1、对微环滤波器的工作原理进行了深入的分析,并用耦合模理论给出了微环滤波器的透射谱公式。同时给出了微环滤波器重要性能参数的表达式,分析了结构参数对其性能的影响。2、提出了一个基于并联微环结构的滤波器,该滤波器由一串互相之间不直接耦合的微环和两根直波导组成。分析结果表明：当微环的数目大于或等于6个时,该微环滤波器的透射谱具有明显的平顶陡边特性。当微环数目为6个时,其-0.5dB、-3dB、-20dB的带宽分别为0.8nm、1.6nm、1.9nm,满足波分复用系统(WDM)的要求。同时我们发现此种并联微环滤波器的平顶陡边特性和旁瓣之间存在一个矛盾关系：当微环与bus波导的耦合系数较大时(比如为0.6),其透射谱具有很好的平顶陡边特性,但旁瓣较大：当微环与bus波导的耦合系数较小时(比如为0.14),其透射谱成三角形状,但几乎没有旁瓣。因此对于此种滤波器需要我们在平顶陡边特性和旁瓣之间做一个折中。3、提出了一个基于金属纳米棒的表面等离子体波导。该波导由两串基端互相连接的金属纳米棒组成。通过将纳米棒的底部连接起来,我们在此波导中引入了一种新的相互作用机制-传到电流交换,从而减小了波导的传输损耗。理论分析表明：此种等离子波导在1.55μm处的传输长度达到20.87gm,远大于传统的基于金属纳米棒结构的表面等离子体波导。4、提出了一种基于核壳结构的表面等离子体波导,并分析了基于此种波导结构的微环滤波器的性能。理论分析表明：基于此种波导结构的表面等离子体微环滤波器的3dB线宽为1.7nm,消光比为23dB,均比传统的表面等离子体微环滤波器的性能要好。5、设计并制作了一个基于SOI晶片的单微环滤波器。测试结果表明,对于微环半径为7μm,波导间隔为1.8μm,波导截面为300x250nm的微环滤波器,其自由谱范围为18nm, drop端投射谱的消光比为15dB,through端透射谱的消光比为5dB。更多还原

【Abstract】 Recently, microring resonators have received considerable attention due to their advantages of ultra-narrow3dB bandwidth, compact structure and suitability for large-scale integration. However, the integration degree of photonic integration circuit is restrained by the fact that it is impossible to downscale the size of dielectric based microring resonators into the regime of subwavelength due to the diffraction limit. In order to overcome the diffraction limit, Surface Plasmon Polaritons (SPPs) are employed to realize the microring resonators. This is due to the fact that metal could confine the light tightly near its surface and transport the energy in the regime of subwavelength, and the size could then be reduced.In this article, we have investigated the working principles of dielectric based and SPPs based microring resonators, separately. And then the experiment procedures are given thorough introduction. The followings are the achievements of the article:1. We have investigated the working principles of microring resonators and presented the formulas for the transmission spectrum. In addition, the formulas for the performance parameters of microring resonators are presented and then the impact of the change of structural parameters on the performance is analyzed.2. We have proposed and designed a parallel microring resonators based filters, which is composed of a series of microrings and two bus waveguides. Theoretical analysis reveals that the proposed microring filters clearly exhibit the character of steep-edge and flat-top spectrum when the number of microrings is not less than six. It is demonstrated that when the number of microrings is six, the-0.5dB、-3dB、-20dB linewidth of the proposed filer is0.8nm,1.6nm,1.9nm, separately, which definitely meets the requirement of WDM system. Furthermore, a trade-off in terms of the steep-edge and flat-top character and side band is needed:the characteristics of flat-top and steep-edge is well presented with a large side band at a large coupling coefficient (e.g.0.6), while the characteristics of flat-top and steep-edge is nearly missing with a small side band at a small coupling coefficient (e.g. 0.14).3. A nanorods based SPPs waveguide is proposed. The transportation loss is reduced significantly by introducing additional interaction mechanism named conduction current exchange, which is realized by connecting the base end of each nanorod. Simulation results reveal that the transportation length of the proposed waveguide is as long as20.87μm at the wavelength of1.55μm, far larger than that of traditional nanorods based SPPs waveguides.4. A SPPs waveguide based on a core-shell structure is proposed, and then its application in microring resonators is analyzed. Simulation results reveal that for a microring resonator based on such a waveguide, the3dB line-width is1.7nm and the extinction ratio is23dB, which are both better than that of conventional SPPs microring resonators.5. A microring resonator based filter is fabricated on a SOI wafer. The radius of the microring is7μm, gap width between microring and bus waveguide is1.8μm, and the waveguide cross-section is300x250nm. The experiment results reveal that the free spectral range is18nm, extinction ratio for the transmission spectrum at drop and through is15dB and5dB, separately.更多还原