【作者】 郭艳艳；

【导师】 侯蓝田；

【作者基本信息】 燕山大学 ， 电路与系统， 2010， 硕士

【摘要】 随着光子晶体光纤理论研究的深入和制作工艺的完善,光子晶体光纤的应用领域得到了不断的拓展,并推动了光子晶体光纤的实用化进程。现在,光子晶体光纤的制作技术已经得到很大的提高,人们已经能拉制出各种结构复杂的光子晶体光纤。但是,所有理论方面的研究最终还要归于实验验证才能充分表明其正确性。本文从实验测量和数值模拟两个方面对光子晶体光纤的数值孔径和模场直径进行了研究。首先阐述了光子晶体光纤性能测试的现状,总结了传统光纤数值孔径、模场直径测量方法的优缺点。然后根据实际的需要提出了实验方案,设计用光谱仪来测量光子晶体光纤的数值孔径,在光波长为500~1 100 nm范围内研究了光波长、包层空气孔直径、孔间距等对光纤数值孔径的影响,并与多极法的理论模拟结果进行了比较。通过测得的不同光波长下的数值孔径对光纤的非线性系数、宏弯损耗、截止波长、模场面积等与光波长有关的参数进行了计算和分析。其次通过研究传统光纤模场直径的测量方法,对光子晶体光纤模场直径的测量,引入一个基于横向位移法和光斑法原理的实验系统来实现。在现有实验条件下自行搭建实验平台,测量了课题组拉制的三种不同结构的光子晶体光纤,计算了光子晶体光纤的模场直径,用CCD观察了光纤的模场分布,并用matlab程序将光纤的模场转化成三维光强分布图。最后基于光子晶体光纤结构设计灵活的特点,利用多极法对光子晶体光纤的几何结构和材料特性进行了深入的理论分析和数值计算,设计出一种新颖结构的大模面积单模掺镱光子晶体光纤,这对高功率光子晶体光纤激光器、放大器的发展具有重要意义。更多还原

【Abstract】 With the improvement of the numerical methods used in photonic crystal fiber analysis and the maturity of the fabrication technology, the application prospects of photonic crystal fiber have been continuously expanding and the practical process of photonic crystal fiber has been improved. Now, the fabrication technology of photonic crystal fiber has been greatly improved, a variety of photonic crystal fibers with complex structure have can be drawn out. However, all the theoretical studies shoud be proved its correctness by experiments. In this paper, the numerical aperture and mode field diameter of photonic crystal fiber are studied, including numerical simulation and experimental measurement.Firstly, it describes the actuality of the measurement of photonic crystal fiber and the advatage and disadvatage of traditional measurement method of numerical aperture and mode field diameter. Then it proposes using spectrometer to measure the numerical aperture of photonic crystal fiber and investigates the impact of the wavelength, the diameter of air-hole and the pitch on numerical aperture with wavelengh at 500~1 100 nm,and the measurement results are compared with simulation results. According to the measured numerical aperture, the parameters of fiber related with wavelength can be better studied, such as: the non-linearity coefficient, macro-bending loss, the effective mode area, cut-off wavelength and so on.Secondly, according to studying the traditional measurement method of numerical aperture and mode field diamete, it proposes the scheme to measure the mode field diameter of photonic crystal fiber based on lateral displacement method and spot method, then set up the experimental arrangement. By measuring three kinds of photonic crystal fiber which are fabricated by our laboratory, the mode field distribution of photonic crystal fiber can be received. The mode field distribution is observed by CCD. The mode field distribution is transformed into a three-dimensional light intensity distribution map by matlab program.Finally, a novel octagonal Yb3+-doped photonic crystal fiber with large mode area is proposed based on the flexible design feature of photnic crystal fiber. The properties of photonic crystal fiber are investigated by multipole method. This fiber is meaningful for the development of fiber lasers and fiber amplifiers.更多还原