【作者】 侯金；

【导师】 周治平；

【作者基本信息】 华中科技大学 ， 光电信息工程， 2011， 博士

【摘要】 随着硅基微电子元器件集成度的不断提高,器件工艺线宽正趋于理论极限,用电子作为信息载体的微电子技术即将面临难以逾越的瓶颈。因此,用光子作为信息载体的集成光电子学成为了亟须发展的方向。其中,继承了现代大规模集成电路成熟的硅基加工技术,并兼具光子晶体完美控制光能力的硅基光子晶体器件自然的成为了研究的热点与前沿。硅基光波导是传递光子信息的通道,是硅基集成光电回路的核心基础器件。以硅基光子晶体波导为核心可以设计出各种功能各异、种类丰富的硅基光电子器件,如硅基微腔、波导、光延迟器、分束器、耦合器、调制器、探测器等,从而极大的推动硅基光电集成领域的发展。因此,本论文以硅基光子晶体为核心,在“国家重点基础研究发展计划(973计划)前期预研专项”(2006CB708310),“国家青年科学基金”(60706013),“湖北省自然科学基金重大项目”(2006ABD002),“华中科技大学自主创新究基金”(M2009026),“武汉光电国家实验室(筹)创新基金”(P080003),和“华中科技大学研究生创新基金”(HF-08-05-2011-230)等的支持下,重点进行了硅基光子晶体的光子带隙研究和新型光子晶体波导器件的机理与器件原型研究,取得了如下成果：(1)采用全三维平面波法,研究了一种新型环形孔光子晶体绝缘体二氧化硅上硅(SOI)非对称平板的光子带隙,比较了新型环形孔光子晶体平板和普通圆形孔光子晶体的带隙。通过研究发现,在很大范围的空气体积填充比内,同样空气体积填充比的优化的环形光子晶体平板和普通圆形孔光子晶体平板相比,具有更大的光子带隙。例如,对于空气填充比为15%的时候,与普通圆形孔光子晶体平板相比,在环形光子晶体平板中观察到了将近两倍的光子带隙增强。(2)讨论了硅基光子晶体波导中带边慢光的限制因素,研究了零色散型光子晶体宽带慢光波导的机理。在此基础上,设计了一种新型对称边界环宽带低色散光子晶体慢光波导。通过调节这种边界环波导环中的内径大小,可以使得光子晶体导模色散曲线中出现一个线性段,从而实现低色散宽带慢光。时域有限差分仿真表明,在一种优化的这种慢光波导中可以实现中心波长在1550纳米,带宽为2.3纳米的群折射率为74.4的慢光传输。(3)研究讨论了色散补偿型光子晶体宽带慢光波导的机理。在此基础上,设计了一种新型啁啾沟道光子晶体耦合慢光波导。通过调节这种波导的结构参数,可以获得一种理想的“座椅状”导模色散曲线。然后再对这种波导的宽度进行啁啾,可以实现宽带低色散慢光。在时域有限差分仿真实验中,成功地获得了中心波长在1550纳米,带宽为20纳米的宽带慢光传输。并且,这种波导能够在低折射率非线性材料沟道结构中实现慢光与光控制,可望用于高速光信号处理以及加强光与物质的相互作用等领域里面。(4)探讨了光子晶体的自准直原理,利用环形光子晶体比普通光子晶体多一个自由度的优势,设计了一种新型宽带偏振无关自准直波导。这种偏振无关自准直波导不但能同时工作于横电场模式和横磁场模式状态下,并且在中心波长为1550纳米时具有约102.9纳米宽的偏振无关自准直传播的带宽。因此,可以用于各种宽带的可重构波导器件和高密度光电集成器件,如偏振分束器,偏振耦合器等。更多还原

【Abstract】 With the fast increasing of microelectronic devices integration in a single silicon chip, device fabrication line width is approaching to the theoretical limit. Therefore, microelectronics technology which uses electrons as information carriers will soon face formidable bottleneck. Thus, optoelectronics integration which uses photons as the information carrier is thought to be the new development direction. Silicon based photonic crystal, which inherits of the mature silicon processing technology of modern large scale integrated circuits and also has the perfect ability to control light due to their photonic band gap, naturally becomes to be the research hotspot. Silicon based photonic waveguides is the information transmission channel, and also is one of the key foundation devices for silicon-based integrated optical circuits. In the basis of the silicon based photonic crystal waveguide, a variety of different functions silicon-based optoelectronic devices can be designed and fabricated, such as silicon-based micro-cavity, waveguide, optical delay, splitter, couplers, modulators, detection and so on. Therefore, supported by the National Basic Research Program of China (grant 2006CB708310), Natural Science Foundation of China (grant 60706013), Natural Science Foundation of Hubei (grant 2006ABD002), the Independent Creative Research Foundation of Huazhong University of Science and Technology (grant M2009026), the Creative Research Foundation of Wuhan National Laboratory for Optoelectronics (grant P080003) and the Graduation Creative Research Foundation of Huazhong University of Science and Technology(grant HF-08-05-2011-230), this thesis focus on the photonic band gap characteristic and new types of silicon based photonic crystal waveguide devices:(1) Based on investigations and discussions of the formation mechanism of photonic band gap in photonic crystal, photonic band structures of annular photonic-crystal silicon-on-insulator asymmetric slabs with finite thickness were investigated by the three-dimensional plane-wave expansion method. The results show that for a broad range of air-volume filling factors, annular photonic-crystal slabs can exhibit a significantly larger band gap than conventional circular-hole photonic-crystal slabs. For a noticeable case, approximately a two-fold enhancement of the band gap was observed based on the same configurations except the use of optimized annular holes instead of circular holes. This desirable behavior suggests a potential for annular photonic-crystal silicon-on-insulator slabs to serve as the basis of various optical cavities, waveguides, and mirrors.(2) Based on the investigations and discussion of the flat band slow light mechanism in photonic crystal waveguide, flat band low dispersion slow light in symmetric line defect photonic crystals waveguide formed by adding dielectric pillars in the air holes nearest to the waveguide core is investigated. By adjusting the radii of the new dielectric pillars, a linear band in the photonic band structure appears which denotes low group velocity dispersion. High average group index of 74.4 with 2.3 nm bandwidth centered at 1550 nm wavelength is demonstrated in an optimized waveguide by finite-difference time-domain simulation. The novel photonic crystal waveguide can provide various applications, such as optical buffer memories, efficient optical switches and especially in enhanced light-matter interaction both in the linear and nonlinear regime with a simple and straight structure.(3) Based on the investigations and discussion of dispersion compensation wide band slow light mechanism in photonic crystal waveguide, wideband dispersion-free slow light in chirped-slot photonic-crystal coupled waveguides is proposed and theoretically investigated in detail. By systematically analyzing the dependence of band shape on various structure parameters, unique inflection points in the key photonic band with approximate zero group velocity can be obtained in an optimized slot photonic-crystal coupled waveguide. By simply chirping the widths of the photonic-crystal waveguides in the optimized structure, wideband (up to 20 nm centered at 1550 nm wavelength) slow-light with optical confinement in the low dielectric slot is demonstrated numerically with relative temporal pulse-width spreading well below 8% as obtained from two-dimensional finite-difference time-domain simulations. The wideband slow-light operation of the proposed structures would offer significant potential for novel compact high-speed optical-signal-processing devices in silicon-based systems.(4) Based on the investigations and discussion of photonic crystal self-collimation phenomena and theory, making use of the two freedom adjustable parameters of the annular photonic crystal, the frequency bands for self-collimation at both TE and TM polarizations in square lattice annular photonic crystals are studied systematically by plane wave expansion and finite difference time domain methods. A polarization insensitive self-collimation waveguide in a high dielectric contrast system with bandwidth up to 102.9 nm is demonstrated as an example of the implementation of photonic integration circuits.更多还原