【作者】 张鹏；

【导师】 赵建林；

【作者基本信息】 西北工业大学 ， 光学工程， 2004， 硕士

【摘要】 新千年伊始，人类社会已步入高速传输数据、语音、影像等信息的多媒体因特网时代。作为因特网发展基石的微处理器速度以及通信带宽正以Moore定律飞速发展，光通信系统中关键光电子器件的传统制造技术受到极大挑战。目前市场上还没有低成本的集成光学器件，因此人们必须寻求新的制作技术以适应发展的需求。近年来光辐照法被认为是一种直接、快速、低成本、高效益的集成光波导器件制作技术，备受关注。 本文主要研究利用不同的结构光在光折变晶体中写入各种波导结构的方法。所开展的工作以及得到的结论如下：①从光折变动力学方程组出发对光折变晶体中光致折射率变化进行了理论分析，并建立了由写入光的强度分布得到光致折射率变化分布的数值模拟方法。②在功率密度为毫瓦量级的连续激光辐照下，对LiNbO₃：Fe晶体中的光致折射率变化规律进行了详细的实验研究，并对实验结果进行了理论分析及数值模拟。结果表明：利用不同的结构光辐照LiNbO₃：Fe晶体可以在其中有效的写入波导结构。③对利用柱透镜和光学二元掩模板形成的结构光在光折变晶体中写入平面光波导、Y型光波导以及通道光波导的方法进行了详细的实验研究。并首次提出了利用空间光调制器制作光学掩模板，在光折变晶体中写入具有各种形状以及不同折射率分布的波导乃至整个集成光路的方法。研究结果表明：仅利用SLM形成的结构光辐照可以在薄片晶体或薄膜材料中写入高质量的波导器件。④从理论和实验两个方面对利用双光束和四光束干涉形成的光场在SBN：Cr、LiNbO₃：Fe和KNSBN：Ce晶体中写入平面波导阵列和通道波导阵列的方法进行了详细的研究。并提出了利用一个双光束干涉场以不同的角度两次辐照晶体，在光折变晶体中写入不同通道波导阵列结构的方法。研究结果表明：采用合适的光场强度分布以及合适的外加电场可以在不同光折变晶体中写入平面波导阵列和通道波导阵列。⑤基于马赫-曾德干涉仪光路研究了利用切片干涉法测量光折变晶体中光致折射率变化的方法，并首次提出了利用数字全息术对光折变晶体中光致折射率变化进行可视化的方法。此外，成功地利用上述方法对光写入波导结构的折射率分布进行了测量。 利用不同的结构光辐照光折变晶体，可以制作具有不同结构的光波导以及光波导阵列。这种方法对仪器条件要求很低，而且随着电／热固定以及光／热擦洗等技术的不断成熟，既可以得到永久的波导结构，也可以得到瞬时的波导结构。因此光折变晶体中结构光写入的波导器件可以被用于现有的光通信系统，并且有望被用于动态光互连以及光学神经网络系统。更多还原

【Abstract】 At the beginning of a new millennium, humanity enters into a multimedia internet age with information (e.g. data, sound, and videos) transmitted at a high speed. As the basis of the internet, the microprocessor speed and the amount of available bandwidth increase as Moore’s Law, the traditional fabrication techniques of the key photonics and electronics components face a critical challenge. Currently, there exists no low-cost integrated optical component in commercial systems. Recently, light-induced optical waveguide formation attracts much research interest as a recognized technology for direct, rapid, and cost-effective fabricating of various integrated optical waveguides.This dissertation mainly investigates writing various waveguide structures in photorefractive (PR) crystals by structure light irradiation method. The main contents of this dissertation are as follows: (1)According to the set of equations governing the PR process, index changes in PR crystals induced by writing beams with different intensity profiles are theoretically analyzed and numerically simulated. (2)The index changes induced by cw laser at milliwatt in LiNbO3:Fe crystals are studied experimentally in detail. Furthermore the experimental results are theoretically analyzed and numerically simulated. The results show that waveguide structures can be effectively induced employing structure light irradiation in LiNbO3:Fe crystals. (3) Fabrication methods of planar, Y-branches, and channel waveguides employing structure lights formed by cylindrical lenses and optical binary masks are investigated experimentally in detail. And a novel approach to prepare optical masks by using spatial light modulator for light-induced various waveguides, even a whole circuits is proposed. (4)Fabricating planar and channel waveguide arrays in SBN:Cr, LiNbO3:Fe and KNSBN:Ce crystals under illuminations of two-beam and four-beam interferograms are detailedly investigated both theoretically and experimentally. Moreover a novel approach to fabricate array of three-dimensional waveguides in PR crystals employing illuminations of a pair of mutually coherent or incoherent two-beam interference fields is proposed. Employing writing beams with appropriate intensity distributions and external electric fields along proper directions, arrays of planar and channel waveguides can be fabricated in various PR crystals. (5) Based on Mach-Zehnder interferometer setup, slice-interferometry for measuring light-induced index changes in PR crystal is investigated. And employing digital holography for visualizations of the index changes in PR crystal is first proposed. Additionally, the two approaches are used for measuring the index distributions of light-induced waveguides successfully.Various optical waveguides and waveguide arrays can be fabricated by irradiations of different structure lights. This technique is very convenience, and combines with the electrical/thermal fixing and optical/thermal erasing techniques both permanent and instantaneous waveguides can be obtained. Structure-light-induced waveguide devices in PR crystals can be used for the current optical communication systems, and may be used for optical dynamic interconnection and optical neural network systems.更多还原