【作者】 钟志荣；

【导师】 邱怡申；

【作者基本信息】 福建师范大学 ， 光学， 2005， 硕士

【摘要】 光耦合技术是光通信、光传感以及光集成领域中的关键技术,在未来的全光网络中占据有重要的地位,因此对光耦合理论进行研究是很必要的。本文的主要研究内容有: 第一,借鉴量子力学的一维散射理论方法,计算具有纵向分离的两单模光纤连接损耗理论。此方法是通过求解纵向波动方程,计算考虑由于端面反射后波的相干效应时的回波损耗以及耦合效率,与前人的结果相比较,我们得到更加准确的结果。在这基础上,用该方法计算两光纤同时具有角向偏离和纵向偏离时的耦合效率; 第二,为了提高单模光纤到多模光纤的耦合效率,我们利用一自聚焦透镜(G-lens)对单模光纤的模场半径进行扩束,使其与多模光纤的基模模场半径相匹配,在保证只激励多模光纤中基模的前提下,提高单模光纤到多模光纤的耦合效率;多模光纤系统中由于多模光纤本身的特点(模间色散严重),使得该系统的传输带宽比较低,为了提高现有的多模光纤通信系统传输速率,提出利用单模光纤对多模光纤系统进行滤模,在通信线路中滤掉高阶模降低模间色散,以提高多模光纤系统的传输带宽。 第三,将多模光纤出射光看成准单色部分相干光,采用几何光学和波动光学相结合的方法,分析多模光纤准直器的出射光场的特点,得到多模光纤准直器的输出光场满足高斯分布,在满足物象关系下,高斯分布具有最小光斑半径的结论。更多还原

【Abstract】 The optical coupling technology is the key technology in optical communication, optical sensor and optical integration, and it will hold the primary status in optical networks in the future. So it is necessary to study the optical coupling theory deeply. The thesis comprises the following:Firstly, we present a new method that is similar to that of one dimension scattering theory in quantum mechanics. And this method can be used to calculate the return loss and coupling efficiency with a longitudinal separation between two single mode fibers. A more accurate expression of the return loss can be obtained by solving the longitudinal wave equation in our method, which takes into account the coherence effect mentioned above. As the same time, the coupling efficiency of two fibers with an angular misalignment and with a longitudinal separation between two single mode fibers was calculated.Secondly, in order to increase the coupling efficiency of single mode fiber to multimode fiber, The G—lens is used to expand the mode field radius of single-mode fiber. The girdling radius of single mode fiber has been expanded to match the girdling radius of fundamental-mode of multimode fiber, and to excite the fundamental-mode of multimode fiber, improves the coupling efficiency from single-mode fiber to multimode fiber.Because of the disadvantage of multimode fiber, such as mode dispersion, and the bandwidth of multimode fiber system is limited. In order to improve the bandwidth of multimode fiber system, a mode filter device that made by a single mode fiber is adopted.Thirdly, according to the statistical optics theory, the output of multimodefiber was taken as a quasi-homogeneous source; geometry optics and wave-guide optics were taken to analyze the output of multimode fiber collimator. We obtain that the output field of multimode fiber satisfy Gauss distributing.更多还原