高Q值回音壁模式光学微腔研究与实现

发布时间：2018-01-13 05:26

本文关键词：高Q值回音壁模式光学微腔研究与实现　出处：《太原理工大学》2016年博士论文　论文类型：学位论文

【摘要】：回音壁模式光学微腔高品质因子、小模式体积的特性,使其在光传感、光通信及低阈值激光光源等诸多方面具有非常大的应用潜力,吸引了研究人员的广泛关注。其中,高品质因子是提高传感器灵敏度、降低激光阈值、增强各种光学效应的关键参数。本论文工作集中于高品质因子回音壁模式光学微腔实现,对两种代表性回音壁模式微谐振腔(SOI波导环形谐振腔和二氧化硅空心微泡腔)进行深入的理论和实验研究。SOI波导环形谐振腔具有集成度高,与CMOS工艺相兼容的优点。但由于加工工艺水平的限制,波导表面都不可避免的存在一定的粗糙度。表面粗糙度显著增加了波导的散射损耗,限制了谐振腔品质因子的提高。二氧化硅空心微泡腔具有高品质因子及制备工艺条件简单的优点,但是如何制备出结构对称、厚度均匀的高品质因子微泡腔一直是困扰许多研究者的难题。本文针对上述两种光学微腔所面临的关键问题,从理论和实验两方面进行深入研究,主要研究内容如下:1、对光波导传输损耗理论进行分析。提出了一种基于傅里叶变换和时域差分的高精度建模分析方法。利用这种方法对光波导表面粗糙度进行建模,并分别研究了相关长度和均方根粗糙度对直波导传输损耗及波导谐振腔谐振特性的影响。通过理论计算及实验测试结果与仿真结果的对比,验证了所建立模型及其分析结果的正确性。2、深入研究了光波导表面形貌表征方法,指出目前在纳米光波导侧壁形貌表征方面存在的问题。对氢退火表面光滑化机理进行分析,搭建了氢退火实验装置并进行高温氢退火实验。AFM测试结果表明,氢退火前后波导表面粗糙度从1.75nm降低到0.59nm,证明了氢退火光滑工艺的可行性。3、分析目前光纤微泡腔制备技术存在的问题和不足,提出一种基于高压气体辅助电弧放电技术的低成本、超薄、空心光纤微泡的制备方法。通过采用弱放电、缓释压强的方法,最终制备出了结构对称、厚度均匀(2μm)、Q值达107的空心微泡腔。4、从光纤微泡压强传感器基本原理出发,利用Ansys软件对微泡光学谐振腔的力学特性进行分析。采用FP干涉方法,对微泡腔填充气压与其顶部形变之间关系进行实验测试。基于锥形光纤耦合的方法,研究微泡腔作为压强传感器的高灵敏度特性。本论文针对提高光学微腔品质因数这一核心问题开展研究,主要研究成果有如下两个方面:1、通过理论仿真揭示了表面粗糙度对波导传输特性的影响;利用氢退火方法降低了波导表面粗糙度,减小了波导表面散射损耗,提高了波导环形谐振腔的Q值。2、解决了高品质因子微泡腔制备过程中面临的结构不对称,厚度不均匀的问题。本论文研究成果可为实现高Q值回音壁模式光学微腔提供理论和技术支持,进一步促进光学微腔的应用和发展。
[Abstract]:The characteristics of high quality factor and small mode volume of echo mode optical microcavity make it have great application potential in many fields such as optical sensing, optical communication and low threshold laser light source. Among them, the high quality factor is to improve the sensitivity of the sensor and reduce the laser threshold. This paper focuses on the realization of high quality factor echo wall mode optical microcavity. The theoretical and experimental studies of two typical echo wall mode microresonators, SOI waveguide ring resonators and silicon dioxide hollow microbubble cavities, are carried out. The SOI waveguide ring resonators are highly integrated. It is compatible with CMOS process, but due to the limitation of processing technology, some roughness is inevitable on the waveguide surface, and the surface roughness increases the scattering loss of the waveguide. The improvement of cavity quality factor is limited. Silica hollow microbubble cavity has the advantages of high quality factor and simple preparation conditions, but how to prepare a symmetrical structure. The uniform thickness of high quality factor microbubble cavity has been a difficult problem for many researchers. In this paper, the two kinds of optical microcavity facing the key problems, from the theoretical and experimental aspects of in-depth research. The main research contents are as follows: 1. The transmission loss theory of optical waveguide is analyzed. A high-precision modeling and analysis method based on Fourier transform and time-domain difference is proposed, which is used to model the surface roughness of optical waveguide. The effects of correlation length and root-mean-square roughness on the transmission loss and resonant characteristics of the waveguide resonator are studied respectively. The theoretical calculation and experimental results are compared with the simulation results. The correctness of the model and its analysis results are verified. 2. The surface morphology characterization method of optical waveguide is studied in depth. The problems existing in the characterization of the side-wall morphology of nanoscale optical waveguides are pointed out. The mechanism of surface smoothing by hydrogen annealing is analyzed. The experimental results of hydrogen annealing and high temperature hydrogen annealing show that the surface roughness of waveguide decreases from 1.75 nm to 0.59 nm before and after hydrogen annealing. The feasibility of hydrogen annealing smoothing process is proved. 3. The problems and shortcomings of the current fabrication technology of optical fiber microbubble cavity are analyzed. A low cost and thin arc discharge technology based on high pressure gas assisted arc discharge is proposed. By using the method of weak discharge and sustained release pressure, the hollow microbubbles with symmetrical structure and uniform thickness of 2 渭 m ~ (-1) Q value up to 107 were prepared by using the method of weak discharge and sustained release pressure. Based on the basic principle of fiber optic microbubble pressure sensor, the mechanical properties of optical resonator are analyzed by Ansys software. FP interference method is used. The relationship between the filling pressure and the deformation at the top of the microbubble cavity was tested experimentally. The method of tapered fiber coupling was used. The high sensitivity of microbubble cavity as a pressure sensor is studied. In this paper, the core problem of improving the quality factor of optical microcavity is studied. The main research results are as follows: 1. The influence of surface roughness on the propagation characteristics of waveguide is revealed by theoretical simulation. The surface roughness of the waveguide is reduced by hydrogen annealing, the scattering loss of the waveguide surface is reduced, and the Q value of the waveguide ring resonator is increased. 2. The problems of asymmetric structure and uneven thickness in the preparation of high quality factor microbubble cavity are solved. The research results in this paper can provide theoretical and technical support for the realization of high Q value echo wall mode optical microcavity. Further promote the application and development of optical microcavity.
【学位授予单位】：太原理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN252

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