基于非线性材料的光子晶体逻辑门

发布时间：2018-01-24 07:44

本文关键词： 光子晶体石墨烯硅纳米晶逻辑门　出处：《深圳大学》2017年硕士论文　论文类型：学位论文

【摘要】：光电子器件和全光器件跟传统的电子器件相比,有许多更优良的特性,如更快的运算速度和更低的能耗,主要发展前景在于信息通信及处理领域,有利于未来复杂低能耗要求的模块化和系统化集成。本文通过引入非线性材料石墨烯和硅纳米晶,在二维光子晶体中构造合适的环形谐振腔,实现了性能优异的全光逻辑门。本文提出的全光逻辑门以小尺寸的光子晶体为基础,器件基于结构简单常见的环形谐振器,逻辑响应十分优异。本文以环形谐振腔为例子,引入了由H.A.Haus提出的时域耦合模理论,深入的分析了三端口系统中输入场在波导和环形谐振腔之间的耦合机制。本文还系统的分析了谐振频率、输出端口透射率跟缺陷品质因子、非线性材料损耗和波导衰减率的关系。为了便于数字模拟,本文采用等效模型,用一等效层取代石墨烯及其附近的介质。光子晶体的能带结构决定了器件的工作波段,在这里我们通过平面波展开法研究了器件的能带结构。通过参数扫描,获得较大禁带的光子晶体,并且我们通过时域有限差分法分析了石墨烯材料的添加对光子晶体能带的影响。光子晶体结构参数的选择影响光子晶体光子禁带位置和宽度,并且要得到合适的谐振模位置必须把石墨烯材料添加在光子晶体中的合适位置。通过前期扫描及优化,我们设计了合适的光子晶体结构参数,得到完整光子晶体的禁带的归一化频率范围为0.324-0.464。我们的逻辑器件基于环形谐振器,器件设置最佳工作波长为1.55?m,而光子晶体禁带的中央归一化频率为0.394,与最佳工作波长相符。本研究中构造了基于包裹非线性石墨烯层介质柱波导光子晶体环形谐振腔的受控逻辑非门、开关,还构造了基于非线性石墨烯和硅纳米晶材料的非线性非门、受控非门和受控或非门。本文根据石墨烯和硅纳米晶的非线性效应,分析了全光开关和受控逻辑非门的逻辑响应,实现了回波损耗高以及消光系数高的优异的逻辑器件。其中开关的消光比为36.8dB,最小回波损耗也有16.4dB,对于受控逻辑非门,消光系数达到了32.9dB。构造了多层石墨烯和硅纳米晶为非线性材料的非门和受控非门,逻辑响应好以及消光系数高。非线性非门的关闭功率仅为62mW/?m,消光比为41dB。对于受控非门,消光比也有22.1dB。基于双环形谐振腔的受控或非门也表现出很好的逻辑响应。
[Abstract]:Compared with traditional electronic devices, optoelectronic devices and all-optical devices have many better characteristics, such as faster computing speed and lower energy consumption. The main development prospects are in the field of information communication and processing. This paper introduces the nonlinear materials graphene and silicon nanocrystals to construct an appropriate ring resonator in two-dimensional photonic crystals. An all-optical logic gate with excellent performance is implemented. The proposed all-optical logic gate is based on a small size photonic crystal and the device is based on a simple and common ring resonator. The logical response is very excellent. In this paper, the time-domain coupled mode theory proposed by H. A. Haus is introduced, taking the ring resonator as an example. The coupling mechanism of the input field between the waveguide and the ring resonator in the three-port system is analyzed in depth. The resonant frequency, the transmission of the output port and the defect quality factor are also analyzed systematically in this paper. The relationship between the loss of nonlinear materials and the attenuation rate of waveguides. In order to be convenient for digital simulation, an equivalent model is used in this paper. An equivalent layer is used to replace graphene and its surrounding medium. The band structure of photonic crystal determines the working band of the device. Here we study the energy band structure of the device by plane wave expansion method. Photonic crystals with large bandgap have been obtained. The influence of the addition of graphene on the photonic crystal band is analyzed by the finite-difference time-domain method, and the position and width of photonic band gap are affected by the choice of photonic crystal structure parameters. In order to obtain the appropriate resonant mode position, graphene materials must be added to the appropriate position of photonic crystal. Through the pre-scanning and optimization, we designed the appropriate parameters of photonic crystal structure. The normalized frequency range of bandgap for complete photonic crystals is 0.324-0.464.Our logic devices are based on ring resonators and the optimal operating wavelength is 1.55? And the central normalized frequency of photonic crystal bandgap is 0.394. In this study, a controlled logic gate and switch based on a photonic crystal ring resonator encased in a nonlinear graphene layer dielectric cylindrical waveguide has been constructed. The nonlinear nongate, controlled gate and controlled or ungate based on nonlinear graphene and silicon nanocrystalline materials are also constructed. In this paper, the nonlinear effects of graphene and silicon nanocrystalline are discussed. The logic response of all-optical switch and controlled logic gate is analyzed. The excellent logic devices with high echo loss and high extinction coefficient are realized, in which the extinction ratio of switch is 36.8 dB. The minimum echo loss is 16.4 dB, and the extinction coefficient is 32.9 dB for the controlled logic gate. The multilayer graphene and silicon nanocrystalline are the non-gate and the controlled gate for nonlinear materials. The logic response is good and the extinction coefficient is high. The closing power of the nonlinear non-gate is only 62 MW / r? M, extinction ratio is 41 dB. For controlled non-gate, extinction ratio is 22.1dB.The controlled or non-gate based on double ring resonator also shows good logical response.
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O734;TN256

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