All Solid Polarization Maintaining Photonic Crystal Fibers And Their Functional Devices

Compared to the conventional polarization-maintaining fibers (PMFs), polarization-maintaining photonic crystal fibers (PCFs) own a host of advantages, for instance, fine temperature stability, the polarization state can propagate stably in long transmission, validly repressing the polarization mode dispersion and so forth. Therefore, the PM-PCFs will definitely play an essential role in such fields as fiber optic gyro (FOG), fiber optic sensing, tunable fiber laser, polarization splitter/combiner and so forth, in future all optical networks.With the appearance and the development of the multi-core PCFs, an increasing number of researchers has shown intense interests on the functional devices based on the multi-core PCFs. Integrating the active and passive components into PCFs will lead to a downscale in the device dimensions and weight, and can effectively avoid the variation and inconsistence caused by the assembly, fixing and adjustment in each moveable parts, thereby enhancing the performance and stability of the optical integrated devices. However, it is too difficult to avoid structural deformations and holes collapse during the fiber drawing, especially for the fusion splicing between a conventional fiber and a PCF. To avoid these problems, the all solid PCFs are employed to design the PMFs and the functional devices in this paper.In this paper, we introduce the development history of the PMFs, the trend and the development, the merits and demerits of the PCFs, PM-PCFs, all solid PCFs, and the functional devices based on PCFs in the first chapter. In the second chapter, we firstly present a bunch of numerical methods which are used to analyze the PCFs in brief. Then we introduce the full vector finite element method (FEM) and the full vector beam propagation method (BPM) in detail, which are used in this paper, including the development, computational procedure, and fundamental principles of the FEM, the fundamental principles of the perfectly matched layers (PMLs), the development and the fundamental principles of the BPM. In the third chapter, we design and analyze the squared lattice and the triangular lattice all solid PM-PCFs through using the full vector FEM. Numerical results show that the approximately maximum single polarization bandwidth of the squared lattice and the triangular lattice PM-PCFs are 137nm and 238nm, respectively, which means the single polarization PCFs based on the triangular structure possess more excellent single polarization properties. Then we analyze the polarization characteristics of an improved all solid single polarization PCF, the dispersion, confinement loss, and the effective mode area are studied as well. The research results show that the single polarization bandwidth is equal to 672nm. Furthermore, the birefringence of PCF based on this structure can reach 10-2 through adjusting the structural parameters. In the fourth chapter, we firstly design and study an all solid 1x4 PCF power splitter by using the combination of the full vector FEM and the full vector BPM, the cross section of the splitter is simple, which results in a lower requirement to drawing technique. In addition, two types of all solid PCF polarization splitters based on the modes interference effects and the mode-sorting effects are designed, respectively. Study results show that the former owns higher extinction ratio, while the latter owns wider working bandwidth.