基于石墨烯新材料的全光纤调制器件研究

发布时间：2018-04-29 15:59

  本文选题：石墨烯 + 光电调制器件　； 参考：《浙江大学》2015年博士论文

【摘要】：光通信技术在最近几十年间取得了巨大的进步,也与我们的生活息息相关。而光通信中光电器件的设计尤为重要,伴随着光通信技术的巨大进步,光电器件的性能也被赋予了越来越高的要求。目前光电器件普遍存在着尺寸较大、带宽较窄、速度较慢等等亟待改善的问题。特别是调制器,随着高速通信的飞速发展,对更高带宽,更小半波电压以及更小的尺寸的调制器提出要求,基于新材料的调制器成为人们研究的热点。因此本文将二维新材料石墨烯和传统的光电器件相结合,并利用全光纤结构共同设计光电器件,结合了新材料石墨烯优越的光学性能和全光纤结构在未来全光纤光通信中应用的潜力,探索了具有高性能的光电器件。本论文对基于新材料石墨烯的全光纤器件进行了较为深入的研究。首先探究了石墨烯光电器件的理论模型以及基于石墨烯的波导调制器和偏振控制器,并且对基于石墨烯结构的调制器的原理进行了完整深入的理论分析。在此基础上,本论文对现有的波导结构做出了改进.提出了两种全光纤结构的石墨烯相位调制器和石墨烯吸收调制器,并进行了仿真和实验分析。除此之外,受全光纤调制器的启发,本论文又提出了一种全光纤石墨烯可调偏振控制器,并进行了理论和仿真验证,提出的偏振控制器具有大的消光比,宽的工作范围和在一定范围不受温度影响等优势,并且第一次实现了光纤上的偏振态可调。本论文主要的工作和创新点如下1. 针对传统光调制器存在的诸如调制带宽不够高,调制效率低和无法更好地光集成等问题,总结了新材料石墨烯应用在光调制器的研究,对石墨烯的光学特性和波导特性做了深入的理论分析,并提出了一些之前研究的不足,特别是文章中详细分析比较了石墨烯作为各向异性和各向同性介质时数值计算的不同,文章将石墨烯作为各向异性来考虑,更正了之前大多数石墨烯调制器研究中将石墨烯作为一种各向同性介质的考虑,使之更接近于实际情况。2. 将新材料石墨烯和全光纤结构相结合,提出全光纤结构的石墨烯电光调制器,分别利用有效折射率的实部和虚部变化实现了相位调制器和吸收调制器并用数值仿真和理论数理方法对其进行了分析和计算。运用两种基于不同工作原理的电磁波仿真软件Comsol和FDTD分别进行了二维和三维仿真,来验证结果的正确性。同时结合数理分析方法,验证了仿真的正确性。并且第一次发现了在一定的化学势范围内,相位和化学势之间的准线性关系以及相位和外加电压之间的准二次平方关系。同时提出的利用石墨烯结构有效折射率的虚部变化来实现的电吸收调制器,相较传统的三五族电吸收调制器具有可实现高消光比、小尺寸等多种优势。3.实验上论证了提出的全光纤石墨烯调制器的可行性,实验包含结构方案的确定、石墨烯的制备和转移以及电极的设计等全部加工过程,通过搭建一个完整的微波光子链路,实现了100 MHz信号的调制,并对实验结果进行了分析,主要分析了该调制器设计中存在的一些问题以及调制带宽不高的原因,并提出了实验的后续优化方案。4. 本论文提出了一种石墨烯全光纤结构的可调偏振控制器,该方案将石墨烯均匀生长在光纤的表面,通过改变不同方向上石墨烯的外加电压,获得水平方向偏振态通或者垂直方向偏振态通的偏振控制器,从而在一个光器件上实现了偏振可调。利用新材料石墨烯,设计了一种全光纤结构的偏振态可调偏振控制器。同时该偏振控制器具有大的消光比,宽的工作范围和在一定范围不受温度影响等优势。本论文主要对新材料石墨烯全光纤调制器件进行了研究,提出了两种全光纤石墨烯调制器和一种全光纤石墨烯可调偏振控制器。本论文采用了理论建模分析、仿真数值计算、实验设计验证和结果分析等研究方法,并取得了一定的成果,但由于实验条件的限制,部分方案还只停留在仿真结果上,有待后续实验的进一步验证。
[Abstract]:Optical communication technology has made great progress in the last few decades, and it is closely related to our life. The design of optoelectronic devices is particularly important in optical communication. With the great progress of optical communication technology, the performance of optoelectronic devices has been given higher and higher requirements. Narrow, slow, and so on. In particular, the modulator, with the rapid development of high speed communication, demands for higher bandwidth, smaller half wave voltage and smaller size modulator. The modulator based on the new material has become the hot spot of research. Combined with the use of all optical fiber structures to jointly design optoelectronic devices, combined with the superior optical properties of new materials graphene and the potential of all optical fiber structures in the future full optical fiber optical communication, a high performance optoelectronic device is explored. This paper has carried out a more in-depth study of all fiber devices based on the new material of graphene. The theoretical model of graphene optoelectronic devices and the waveguide modulator based on graphene and the polarization controller are explored, and the principle of the modulator based on the graphene structure is thoroughly and deeply theoretically analyzed. On this basis, the existing waveguide structures are improved in this paper. Two kinds of all fiber structured graphene are proposed. The phase modulator and the graphene absorption modulator have been simulated and analyzed. In addition, inspired by the whole fiber modulator, a kind of all-optical fiber graphene adjustable polarization controller is proposed in this paper, and the theoretical and simulation verification is carried out. The proposed polarization controller has large extinction ratio, wide range of work and a certain extent. The main work and innovation points in this paper are as follows: 1. for the traditional light modulator, such as low modulation bandwidth, low modulation efficiency and no better optical integration, the application of new material graphene in light modulator is summarized. The theoretical analysis of the optical and waveguide characteristics of graphene is made, and some shortcomings of the previous research are put forward. In particular, the difference between the numerical calculation of graphene as anisotropic and isotropic medium is analyzed and compared in detail. This article considers graphene as anisotropy and corrects most of the previous stones. In the study of the graphene modulator, graphene is considered as an isotropic medium, making it closer to the actual situation..2. combines the new material graphene with the whole fiber structure, and proposes a fully fiber structured graphene electro-optic modulator. The phase modulator and absorption modulation are realized by using the real and imaginary parts of the effective refractive index. The device is analyzed and calculated by numerical simulation and theoretical mathematical method. Two kinds of electromagnetic wave simulation software based on different working principles, Comsol and FDTD, are used to verify the correctness of the results, and the correctness of the simulation is verified by the mathematical analysis method. In a certain chemical potential range, the quasi linear relationship between phase and chemical potential and the quasi two square relation between the phase and the applied voltage. At the same time, the electronic absorption modulator, which is realized by the virtual part change of the effective refractive index of the graphene structure, can achieve high extinction ratio compared with the traditional 35 electric absorption modulator. The feasibility of all optical fiber graphene modulator is demonstrated by.3. experiments. The experiment includes the determination of the structure scheme, the preparation and transfer of graphene and the design of the electrode. By building a complete microwave photon link, the modulation of the 100 MHz signal is realized, and the experimental results are carried out. In this paper, some problems in the design of the modulator and the reasons for the low modulation bandwidth are analyzed, and a follow-up optimization scheme of the experiment.4. is put forward in this paper. A kind of adjustable polarization controller for the whole fiber structure of graphene is proposed in this paper. This scheme makes the graphene uniformly grow on the surface of the fiber and changes the upper stone in different directions. The polarization controller of the polarized state of the horizontal polarization state or the vertical polarization state is obtained, thus realizing the polarization adjustable on a light device. Using the new material graphene, a polarizing polarization controller for all fiber structures is designed. The polarization controller has large extinction ratio and wide operation. In this paper, two kinds of all fiber graphene modulator and a full fiber graphene adjustable polarization controller are proposed in this paper. The theoretical modeling analysis, simulation numerical calculation, experimental design verification and results are used in this paper. Analysis and other research methods, and achieved certain results, but due to the limitations of the experimental conditions, some of the schemes still only remain on the simulation results, which need further verification of the follow-up experiments.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TN929.1;TN761
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本文编号：1820610