【作者】 韩婷婷；

【导师】 刘艳格； 王志；

【作者基本信息】 南开大学 ， 光学， 2013， 博士

【摘要】 微结构光纤将光子晶体微结构引入到光纤截面中,实现了对光的局域化和传播特性的调控。它独特的结构和特性大大地扩展了光纤的应用领域,引起了科学界研究者的极大青睐。微结构光纤中微纳尺度的空气孔结构为实现光纤与其它材料的有机结合提供了条件。将具有特殊光、电、磁、热等特性的功能材料填充入微结构光纤中,实现了光纤优异的导光特性和填充材料特殊的物理性能有机结合,进而可以调控微结构光纤的传导机制、模式耦合、双折射、色散等光学特性,对研究微结构光纤中光与填充物质的相互作用规律以及研制高性能可调控的光纤通信和传感器件具有重要意义。而且借助微结构光纤对光优良的可控特性,又能实现对材料的精确测量和实时操控,从而在生物光子学、微流动力学等领域展现出了很好的应用前景。本文结合国家973计划、国家自然科学基金以及天津市自然科学基金等重点项目的研究目标和内容,针对基于高折射率功能材料填充的微结构光纤的传导机制、模式控制、可调谐特性以及其在可调谐功能器件和传感方面的应用展开了系统深入的理论和实验研究。论文的主要研究工作和创新性成果如下：1、通过对基于高折射率功能材料填充的光子带隙光纤的传导机制、温度和弯曲特性的理论研究,揭示了光子带隙的弯曲和温度可调谐特性以及弯曲调谐特性的温度依赖性,提出将弯曲和温度调控共同作用于功能材料填充的光子带隙光纤中,实现了较没有弯曲调谐时更宽的带隙调谐范围。2、通过对实施弯曲的高折射率功能材料填充的光子带隙光纤的模式分布和模式耦合特性的理论研究,揭示了功能材料填充的光子带隙光纤中弯曲导致纤芯模式与高折射率柱模式耦合的避免相交效应。利用该效应在光子带隙光纤传输窗口中间产生窄带谐振峰,实现了超高灵敏度折射率(温度)光子带隙光纤传感器,获得的传感灵敏度高达32400nm/RIU(-13.1nm/℃),据我们所知该值是当时报道的光纤传感器中的最高值。3、通过控制高折射率功能材料填充的光子带隙光纤和单模光纤熔接时的参数,在熔接处制作了宽度18μm,高度40μm的微型空气腔F-P干涉仪,巧妙利用光纤环路结构将材料填充的光子带隙光纤的透射谱和微型空气腔F-P干涉仪的反射谱相结合,揭示了光子带隙对F-P干涉峰损耗调控的特性。利用光子带隙边界对温度的高灵敏度特性,实现了F-P干涉峰的损耗随温度-1.94dB/℃的灵敏度；利用F-P干涉峰对轴向拉力的高敏感特性,实现了3.25nm/N的拉力灵敏度。结合位于带隙边界F-P干涉峰损耗对温度的高灵敏特性和对轴向拉力的低敏感特性以及带隙外的F-P干涉峰中心波长对轴向拉力的高灵敏度特性和对温度的不敏感特性,实现了对温度和轴向拉力的双参量传感。4、理论分析了选择性填充不同折射率的高折射率功能材料以及不同的选择性填充结构的微结构光纤的模式耦合特性及模式双折射特性,揭示了纤芯模式与高折射率柱模式的耦合特性对光纤双折射特性的调控,实现了具有独特双折射特性的微结构光纤。进一步理论分析了该类双折射光纤实现的Sagnac干涉仪的光谱和传感特性,揭示了光纤的群双折射特性和传感光纤长度对Sagnac干涉仪光谱和传感特性的调控,在零群双折射波长附近可以实现很高的传感灵敏度。5、利用手动选择性填充法和CO2激光器侧向曝光法,实现了不同选择性填充结构的高折射率功能材料填充的微结构光纤,实验研究了其Sagnac干涉仪传输光谱和传感特性,揭示了具有不同群双折射特性的微结构光纤Sagnac干涉仪不同的光谱和传感特性,以及传感灵敏度对波长和温度的强烈依赖性,实现了在56.5℃时高达-45.8nm/℃(112,531nm/RIU)的温度(折射率)灵敏度,以及19.6nm/N轴向拉力灵敏度。更多还原

【Abstract】 The introduction of photonic crystal structure into the fiber cross section of microstructured optical fibers (MOFs) has turned the localization of optical field and control of optical wave propagation into reality. Owing to their distinguished structures and properties that have been exploited in various fiber-optic applications, MOFs have attracted considerable research interests in the past decade. The micro/nano-scale air holes in MOFs make it possible for the combination of optical fibers with functional materials. The outstanding guiding properties of MOFs could be well synthesized with the unique physical characteristics of the optical, electrical, magnetic, and thermal materials infiltrated into MOFs, and thus several optical properties, including guiding mechanism, mode coupling, birefringence, and dispersion, could be controlled, which would be of great significance for the research on the light-matter interaction and development of fiber-based opto-electronic devices as well as sensing components. And moreover, by exploiting the distinguished optical controllability assisted by MOFs, the real-time precise measurement and control could be realized, showing their promising application prospects in various fields such as biophotonics and microfluidic dynamics.Thanks to the support of the National Key Basic Research and Development Program of China, the National Natural Science Foundation of China, the Tianjin Natural Science Foundation. Based on the goal and content of the projects, in this thesis, we have performed systematic as well as in-depth theoretical and experimental investigations on the guiding mechanism, mode control, mode tunability for MOFs infiltrated with high index functional materials. The research work and acquired original outcome are as follows:1. The guiding mechanism, temperature and bending characteristics of the MOFs filled with high index functional materials have been theoretical studied, disclosing the temperature/bending tunability of photonics bandgap and temperature dependence of bending tuning. Simultaneous bending-temperature tuning for the photonic bandgap fiber is proposed, and a wider bandgap tunable range has been achieved compared with the case without applied bending. 2. Based on the theoretical investigation of the mode profile and mode coupling characteristics of the photonic bandgap fiber (PBGF) filled with high index functional material, the avoided-crossing effect between the core mode and high index rod modes have been presented. Owing to this effect, a narrow linewidth resonance peak turns up in the transmission window of the photonic bandgap fiber, and an ultrasensitive refractive index/temperature PBGF sensor has been achieved. Its refractive index and temperature sensitivities reach32400nm/RIU and-13.1nm/℃, respectively, which are the highest values for the fiber sensors reported in related literatures to the best of our knowledge.3. By controlling the splicing parameters between the PBGF filled with high index functional material and single-mode fiber (SMF), an F-P interferometer with18μm in width and40μm in height has been fabricated at the splicing joint. And by employing an optical fiber loop, the transmission spectrum of the PBGF filled with high index material and the reflection spectrum of the microcavity F-P interferometer have been combined to reveal the photonic-bandgap-controlled F-P interferometric fringe loss.Based on the high temperature sensitivity of the photonic bandgap edge, a temperature sensitivity of resonance peak loss as large as-1.94dB/℃has been achieved for our proposed F-P interferometer; by exploiting the highly sensitive spectral response to axial tension, a tension sensitivity of3.25nm/N has been achieved as well. And by using the high temperature sensitivity and low tension sensitivity of the bandgap-controlled interferometric resonance peak loss and the high tension sensitivity and temperature insensitivity of the resonance peak outside the photonic bandgap, simultaneous measurement of temperature and axial tension have been achieved.4. The mode coupling and modal birefringence characteristics of various types of the high-index-filled MOFs with different selective filling configurations and different meterials have been theoretically investigated, revealing the possibility of fiber modal birefringence control through mode coupling between the core mode and high index rod modes, and thus MOFs with unique birefringence feature have been realized. And moreover, the spectral and sensing characteristics of the Sagnac interferometer based on this type of birefringence fiber has been theoretically analyzed, revealing the group-birefringence-and fiber-length-based controllability of interferometric spectrum and sensing characteristics. Theoretical results indicate that ultrahigh sensitivity may be achieved around the resonance peaks with zero group birefringence.5. By using direct manual glue selective filling method and CO2-laser-based side illumination method, the high-index-filled MOFs with different selective filling configurations have been achieved. The interferometric spectrum and sensing characteristics have been experimentally investigated, and experimental results indicate the different spectral and sensing characteristics of the MOF-based Sagnac interferometers with different group birefringence. Their sensitivities show strong temperature responses. The temperature and index sensitivities of-45.8nm/℃and112,531nm/RIU have been achieved at56.5℃, and the tension sensitivity reaches19.6nm/N.更多还原