Mode Property Of Chiral Waveguide With Layered Structure

As a major means of optical transmission, waveguide plays an important role in all-optical networks, optical sensors, optical signal processing and optical experiments. The optical waveguide based on chiral media, which owns optical activity and can control the polarization of light, has a good prospect in the optical signal communication, micro/nano optics, optical coupling and other related fields. In this paper, we studied on the mode property of optical waveguide. With the double-grid finite-difference time-domain method, we researched the propagation of the light field and the influence on the polarization properties in the chiral waveguide with different layered structures.Based on two-dimensional double-grid FDTD method, we got three-dimensional non-dispersive situation FDTD method in chiral media, which two were used to explore the mode property of layered waveguide structures. We described the methods used to realize the algorithm; talked about its applicability and reasonableness; discussed the excitation source, the choice of the boundary conditions and the stability analysis of the programming algorithm and simulation errors. Some examples were compared with the mode transmission theory in chiral media, and then we verified the consistency.By using the FDTD methods, we studied the characteristics of the mode which propagating in the basic layered structure waveguide, and figured out the effect of changing structural parameters. We found out the similarities and differences between the two-dimensional and three-dimensional double-grid FDTD methods. In this way, we worked out the characteristics and patterns of the mode excitation in the medium. And then, the polarization mode conversion characteristics in the three-dimensional structure chiral waveguide was discussed, while we were considering the influence of layered structures containing normal and chiral media.At the last, we studied the mode properties of layered waveguide structures making up of positive and negative chiral medium, and discussed multi-mode propagation in chiral cylindrical waveguide. Specifically, we worked on period structures, which containing opposite chiral media, from planner waveguide to solid waveguide, and confirmed the transmission characteristics of those structures. Combined with previous simulation results, we considered the modes excitation in layered chiral cylindrical waveguide. By listing the field intensity distribution, we expounded the increased and decreased phenomenon of modes in waveguide which had different structures.This paper researched mode property of chiral waveguide with layered structure in two-dimensional and three-dimensional ways. The properties and patterns of the excitation and transmission modes had been summarized. The results could provide assistance for the design of layered waveguides in optics and provide a reference for the study of polarization rotation in chiral medium.