论文标题:掺锗石英光纤紫外光敏性的研究
Study on Photosensivity of Germanosilicate Fiber
论文作者 李剑芝
论文导师 姜德生,论文学位 硕士,论文专业 材料学
论文单位 武汉理工大学,点击次数 12,论文页数 80页File Size2559k
2004-05-01论文网 http://www.lw23.com/lunwen_80649372/ 掺锗光纤;载氢;光敏性;多模
germanosilicate, hydrogen loading,photosensitivity, multi-mode
光纤光栅突飞猛进的发展以及它在通信和传感领域的巨大影响对光纤光敏性的研究提出了要求，而载氢是光纤增敏的一种有效方法。虽然目前有众多的光纤光敏性的研究，但是没有系统的分析掺锗石英光纤增敏的机理，也没有系统的研究载氢条件对光致折射率变化的影响，也没有进行实验测量光致折射率的改变。因此准确把握载氢条件对光纤光敏性的影响，提高光栅的性能已成为一个亟待解决的问题。 本文从掺锗光纤紫外光敏机理、实验和实验分析讨论、以及获得光致折射率方法进行了详细的阐述，分析了影响掺锗石英光纤紫外光敏性的几个因素，根据对紫外光敏性的因素分析，提出了制作光纤光栅的几点参考；并依据掺锗石英光纤光敏性的研究，制作了多摸光纤光栅并对其传感特性进行了实验研究。 本文的所作的主要工作主要包括： 一、研究了未载氢和载氢掺锗石英光纤的紫外光敏性，比较两种光纤的光敏机制，揭示了光纤光栅的形成过程。结果表明：在未载氢的掺锗石英光纤中，起主要作用的光敏机制是色心模型；在载氢掺锗石英光纤中，起主要作用的光敏机制是结构模型。 二、研究了不同载氢压力下和不同载氢时间下的掺锗石英光纤的紫外光敏性，结果表明：掺锗石英光纤的光敏性随着载氢压力的增大，光纤的光敏性逐渐提高；随着载氢时间的延长，光纤光敏性的变化规律符合载氢模型。所得到的一些结论为优化载氢技术提供了依据。 三、对不同载氢条件的光纤刻入光纤光栅，探讨载氢条件与光栅性能的关系，研究退火对光纤光栅性能的影响，所得到的结论对制作光栅提供了依据。 四、通过实验数据和理论数据进行了分析和对比，对目前使用较多的获得光致折射率改变的方法给予了评价。 五、对多模光纤光栅的传感特性进行了实验研究与理论分析，结果表明这种光栅三个反射峰的布喇格波长随温度和轴向应变变化均呈现出良好的线性关系，并且重复性相当好。这些特性与单模光纤光栅的传感特性基本相同。
The study of fiber photosensitivity is proposed because of the rapid development of FBG and its great influence on optical communication and optical sensing, room temperature high pressure hydrogen loading technique has been recognized as an efficient means of achieving ultrahigh photosensitivity. Although a lot of study on fiber photosensitivity is established, the mechanism of germanosilicate fiber and the dependence of photosensitivity on hydrogen loading condition is not studied systematically, the photosensitivity data through experimental measurement is used in this paper. Thus it is a urgent problem to understand exactly the effects of hydrogen-loaded condition on fiber photosensitivity and improve the performance of FBG.This paper explains in detail the mechanism of UV photosensitivity, experiment and experimental analysis and discussion, and the method calculating the UV-induced changes and presents the factors of photosensitivity. The results provide guidance for the fabrication of FBG. Moreover, based on the study of germanosilicate fiber, the multi-mode fiber grating was fabricated and its sensing properties were studied experimentally and theoretically.Much work has been done in this paper:1. The photosensitivity experiment of non-hydrogen-loaded and hydrogen-loaded germanosilicate fiber was done; the mechanism of non-hydrogen-loaded fiber was compared with that of hydrogen-loaded fiber; the process of FBG formation was simulated. The results show: the mechanism is color-center model in the non-hydrogen-loaded fiber; the mechanism is structural model.2. The pressure- and time-dependent fiber photosensitivity was studied in this paper and the UV-induced index changes were measured. The results show: while hydrogen pressure was increased, the photosensitivity gradually increases; while hydrogen-loading time prolongs, the change of photosensitivity is consistent with the evolution of hydrogen concentration. The results provide guidance for optimizing the H2-loading technique.3. The FBG was fabricated and the relation between H2-loading condition and performancesof FBG was discussed; the effects of annealing on FBG were studied. The results provide guidance for FBG writing technique.4. The methods calculating the UV-induced index changes were evaluated by the analysis and comparison of experimental and theoretical data.5. The sensing properties of multimode fiber gratings was investigated experimentally and theoretically in this paper. Experimental results show that the Bragg wavelength of grating in multimode graded-index fiber is linearly dependent on its temperature and axial strain and its repeatability is good. The characteristics are similar to that of a conventional Bragg grating in single-mode fiber.
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