基于热极化多模光纤的光开关研究

发布时间：2018-04-30 01:01

本文选题：热极化光纤 + 二阶非线性　；参考：《北京交通大学》2017年硕士论文

【摘要】：石英玻璃材料在结构上具有宏观反演对称性,不具有二阶非线性光学效应,而热极化技术可以打破这种结构的对称性,诱导出可观的二阶非线性。本文研究了双孔多模光纤的热极化并设计实现了基于热极化多模光纤的单模—多模—单模(SMS)光开关。对于双孔多模光纤的热极化,研究结果表明,在多模光纤中,双阳极结构的热极化光纤相对于单阳极—单阴极结构具有更高的二阶非线性效应。无论是双阳极结构还是单阳极—单阴极结构,随着极化时间的增大,模式的有效折射率差都是先增大后减小且有峰值出现。在相同极化时间下,模式有效折射率差随纤芯半径和纤芯与阳极之间距离的增大而减小。热极化光纤的纤芯半径越小,阳极与纤芯之间的距离越小,有效折射率差出现最大值的极化时间越小且极值越大。基于二维载流子漂移扩散模型,结合热极化后电场在光纤横截面上的分布,得到了热极化后光纤横截面上折射率变化,设计了基于热极化多模光纤的单模—多模—单模(SMS)光开关。研究结果表明,入射波的传输损耗随阳极与纤芯之间距离或纤芯半径的增大而减小,延长热极化多模光纤的长度和降低纤芯和阳极之间距离可以降低开关电压,耗尽层完全覆盖纤芯比耗尽层未覆盖纤芯时所需要的开关电压要小。本文研究的多模光纤热极化和基于热极化多模光纤单模—多模—单模(SMS)光开关对光纤热极化实验和热极化光纤在全光纤器件的应用方面有重要的指导意义。
[Abstract]:Quartz glass material has macroscopic inversion symmetry and no second-order nonlinear optical effect. Thermal polarization technique can break the symmetry of the structure and induce considerable second-order nonlinearity. In this paper, the thermal polarization of two-hole multimode optical fiber is studied and the single-mode, multi-mode single-mode SMS-based optical switch based on thermal polarization multimode fiber is designed and implemented. For the thermal polarization of two-hole multimode fiber, the results show that the two-anode structure has a higher second-order nonlinear effect than the single-anode single-cathode structure in the multi-mode fiber. With the increase of polarization time, the effective refractive index difference of the mode increases first and then decreases with the increase of polarization time. At the same polarization time, the effective refractive index difference decreases with the increase of core radius and the distance between core and anode. The smaller the core radius, the smaller the distance between the anode and the core, and the smaller the polarization time and the maximum value of the effective refractive index difference. Based on the two-dimensional carrier drift diffusion model and the distribution of the electric field in the cross-section of the fiber after thermal polarization, the refractive index changes on the cross-section of the fiber after thermal polarization are obtained. A single mode multimode single mode SMS optical switch based on thermal polarization multimode fiber is designed. The results show that the transmission loss of incident wave decreases with the increase of the distance between the anode and the core or the radius of the core, and the switching voltage can be reduced by increasing the length of the thermally polarized multimode fiber and decreasing the distance between the core and the anode. When the depletion layer is not covered with the core, the switching voltage is lower than that with the depletion layer. In this paper, the thermal polarization of multi-mode fiber and the single-mode SMS-based optical switch based on thermally polarized multimode fiber have important guiding significance for the experiment of optical fiber thermal polarization and the application of thermal polarization fiber in all optical fiber devices.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN253

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