面向谐振式微光学陀螺的高Q平面光波导谐振腔研究

发布时间：2018-11-23 08:25

【摘要】：近年来,谐振式微光学陀螺仪逐渐成为国内外研究的热点之一。以萨格纳克效应为原理的谐振式微光学陀螺在集成化、小型化的发展方面非常具有潜力。谐振式微光学陀螺利用成熟的半导体加工工艺将光源、调制器、探测器以及谐振腔和其他关键器件集成在芯片上,具有体积小、全固态、抗冲击等优点。光波导谐振腔作为谐振式微光学陀螺的核心敏感元件,其光学特性严重影响着陀螺的性能。本文深入分析了光波导谐振腔的光学传输特性,对影响陀螺性能的谐振腔关键特征参数进行了讨论。针对目前光波导谐振腔品质因数低、对谐振腔的结构参数缺乏优化等关键问题开展了系统的研究,提出了二氧化硅光波导谐振腔的设计加工方法,提高了谐振腔的品质因数。论文主要研究内容可分为以下几个方面:1)提出了高Q锗掺杂二氧化硅光波导谐振腔的设计加工方法。针对谐振式微光学陀螺应用对光波导谐振腔的需求,采用有效折射率法和光束传播法对掩埋型锗掺杂二氧化硅光波导进行了分析,计算出了光波导的深宽、最大弯曲弧度等参数。在硅基底上采用等离子体化学气相沉积、光刻以及反应离子刻蚀等工艺制备了锗掺杂二氧化硅光波导谐振腔。所制备的硅光波导的横截面尺寸为6μm×6μm,传输损耗为0.017 dB/cm,光波导谐振腔为环形跑道结构,尺寸为2 cm×3.6 cm。构建了光波导谐振腔谐振曲线测试系统,测试得到所制备的锗掺杂二氧化硅光波导谐振腔品质因数高达107。2)提出了面向谐振式微光学陀螺的光波导谐振腔结构优化方法。结合谐振式光波导陀螺的信号检测原理,从陀螺灵敏度的角度提出了欠耦合状态且谐振深度等于0.75是光波导谐振腔应用于谐振式微光学陀螺的设计参数。通过对谐振腔的分析发现,在不同的耦合状态下,谐振腔所表现出来的谐振谱的半高与谐振深度等特征参量都有所不同。对比了理论上与实验上谐振腔的品质因数、谐振深度在不同耦合状态下的变化趋势,结合谐振式微光学陀螺的三角波调制解调过程,得出了使陀螺灵敏度最大化的光波导谐振腔的特征结构参数。3)提出了双圈光波导谐振腔设计结构。根据谐振腔腔长与谐振谱半高全宽的关系,提出了一种双圈式光波导谐振腔的设计结构。这种结构可以在有限的芯片空间内通过提升光波导谐振腔的腔长来提高其品质因数。论文通过对光纤耦合器进行熔接上不同长度的光纤实验验证了谐振腔的腔长对其品质因数的影响,最高得到了腔长100米,品质因数高达6.74×109的光纤环形谐振腔。在硅基底上,也设计加工出双圈式设计结构,腔长21.6 cm的二氧化硅光波导谐振腔,测试得到其品质因数达到2×107。通过以上研究,制备出高品质因数的光波导谐振腔,并提出了面向谐振式微光学陀螺应用的优化方法和双圈光波导结构,解决了光波导谐振腔现有的关键技术难题,为谐振式微光学陀螺的研究奠定了良好的基础。
[Abstract]:In recent years, the resonant micro-optical gyroscope has become one of the hot spots of the research at home and abroad. The resonant micro-optical gyro based on the Sagnac effect is of great potential in the development of integration and miniaturization. the resonant micro-optical gyroscope integrates a light source, a modulator, a detector and a resonant cavity and other key devices on a chip by a mature semiconductor processing technology, and has the advantages of small volume, all-solid-state, impact resistance and the like. The optical waveguide resonant cavity is used as the core sensitive element of the resonant type micro-optical gyroscope, and the optical characteristic of the optical waveguide resonant cavity is seriously affected by the performance of the gyroscope. In this paper, the optical transmission characteristics of the optical waveguide resonant cavity are deeply analyzed, and the key characteristic parameters of the resonant cavity influencing the performance of the gyroscope are discussed. In the light of the low quality factor of the current optical waveguide resonant cavity, the key problems such as the lack of optimization of the structure parameters of the resonant cavity are studied, the design and processing method of the silicon dioxide optical waveguide resonant cavity is proposed, and the quality factor of the resonant cavity is improved. The main contents of this paper can be divided into the following aspects: 1) The design and processing method of high Q-doped silicon dioxide optical waveguide resonant cavity is proposed. In the light of the requirement of the resonant micro-optical gyro to the optical waveguide resonant cavity, an effective refractive index method and a beam propagation method are adopted to analyze the buried doped silicon dioxide optical waveguide, and the parameters such as the deep width and the maximum bending radian of the optical waveguide are calculated. A doped silicon dioxide optical waveguide resonant cavity is prepared by plasma chemical vapor deposition, photolithography and reactive ion etching on a silicon substrate. The cross-sectional dimension of the prepared silicon optical waveguide is 6. m u.m to 6. m u.m, the transmission loss is 0.017 dB/ cm, and the optical waveguide resonant cavity is an annular runway structure with a size of 2 cm to 3. 6 cm. The resonant curve test system of the optical waveguide resonant cavity is constructed, and the quality factor of the prepared silicon-doped silicon dioxide optical waveguide resonant cavity is high (107. 2), and the structure optimization method of the optical waveguide resonant cavity facing the resonant micro-optical gyroscope is proposed. Based on the principle of the signal detection of the resonant type optical waveguide gyro, the under-coupled state is proposed from the angle of the gyro's sensitivity and the resonance depth is equal to 0.75. The design parameters of the optical waveguide resonant cavity are applied to the resonant micro-optical gyro. Through the analysis of the resonant cavity, the characteristic parameters such as the half-height and the resonance depth of the resonance spectrum exhibited by the resonant cavity are different in different coupling states. Compared with the quality factor of the resonant cavity theoretically and experimentally, the variation trend of the resonance depth under different coupling conditions is compared, and the triangular wave modulation and demodulation process of the resonant micro-optical gyroscope is combined. The characteristic structure parameter of the optical waveguide resonant cavity which maximizes the sensitivity of the gyro is obtained. Based on the relation between the length of the cavity and the half-height of the resonance spectrum, a design structure of a double-loop optical waveguide resonant cavity is proposed. such a structure can improve its quality factor by lifting the cavity length of the optical waveguide cavity within a limited chip space. In this paper, the influence of the cavity length on the quality factor of the resonant cavity is verified by the optical fiber experiment of different length of the optical fiber coupler, and the optical fiber ring-shaped resonant cavity with the cavity length of 100 meters and the quality factor of 6.74-109 is obtained. On the silicon substrate, a double-ring-type design structure is also designed, with a cavity length of 21. 6cm of a silicon dioxide optical waveguide resonant cavity, and the quality factor of the silicon dioxide optical waveguide resonant cavity with the cavity length of 21. 6 cm is measured to reach 2-107. Through the above research, the optical waveguide resonant cavity with high quality factor is prepared, and the optimization method and the double-loop optical waveguide structure facing the application of the resonant micro-optical gyroscope are proposed, and the key technical problems of the prior art of the optical waveguide resonant cavity are solved, and lays a good foundation for the research of the resonant micro-optical gyroscope.
【学位授予单位】：中北大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TH74

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