Study On Slow Light In Photonic Crystal Waveguide

Slow light has wide prospects of application in the fields of optical delay lines, all-optical buffers and optical communications. However, for most technologies of slow light, practical application and miniaturization are very big challenges. Photonic crystal waveguide can generate slow light at room temperature, and its equipment can be made very compact. These create advantages for practical applications. And because of its unique structure of line defect, we can obtain smaller group velocity than most investigations. Though some coupled waveguides with complicated structure can generate slow light and improve its quality, they lead to huge internal reflection loss. This thesis introduces a much simpler structure, single line defect photonic crystal waveguide. By this structure, we reduce internal reflection loss effectively, and debase the group velocity of light transmission.Furthermore, we sum up theoretical analysis methods of photonic crystal. We simulate and calculate the structure of 2D photonic crystal and the transmission characterize of the line defect waveguide, and analyze the influence of the dispersion relation and the group velocity of the defected mode in the waveguide by changing different kinds of structure parameter. By comparing between two kinds of line defect waveguides which one is waveguide formed by removing a row of rods and the other is waveguide that consists of a row of rods being substituted by smaller ones, we analyze the influence of the transmission characterize of the guided mode in the waveguide by changing the filling factor, the radius of defect rods, the refractive index of rods, and the shape of rods. Meanings and values in practical application are pointed out in this thesis.