Research On Several Novel Sturcture Photonic Crystal Fibers And Their Polarization Devices

Nowadays, optical polarization devices are more and more important with the development of communication technology. However, due to diffraction limit, the subwavelength optical polarization devices can not realize miniaturization and integration easily. Currently, the methods to realize subwavelength optical polarization devices are mainly based on photonic crystal structure. In this work, we design several novel structure PCFs. Then we analyse their properties with finite element method(FEM), and have a structure optimization. Moreover, we discuss the application of novel structure PCFs in optical polarization filters and splitters. Our research is significative for the design and application of optical polarization devices. The main contents of this work are as follows:Firstly, we introduce the technology development of photonic crystal fibers(PCFs),especially for the main research progress of the polarization PCFs and surface plasmon resonance(SPR) based PCFs.Secondly, we introduce the main research methods of PCFs, and study the transmission theory and FEM of PCF numercical calculation. Moreover, we interpret the transmission theory of light guided in metal, and analyse the surface plasmon resonance between metal and dielectric.Then, we design two SPR-PCFs for optical polarization filters. The one with a large gold-coated hole has a high polarization filter performance in the communication windows.The other one with two large gold-coated holes is designed to filter different communication windows in different polarization directions at the same time. Moreover,we optimize the structures and analyze the results. Both of the designed SRP-PCFs have high polarization filter performances.At last, we design two dual-core photonic crystal fibers(DC-PCFs) for optical polarization splitters. They are analyzed with FEM. Under the appropriate structure parameters, one of them can respectively realize the high extinction ratios in the communication windows. The other one with filling liquid has a higher polarization split performance in the communication windows. We can see that filling liquid can shorten the polarization split length of DC-PCF, and it is helpful to the device miniaturization.