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Dispersion Characteristics And Regulation Mechanism Study Of Two-dimension Photonic Crystal

Posted on:2011-05-08Degree:MasterType:Thesis
Country:ChinaCandidate:H M DongFull Text:PDF
GTID:2120360308968835Subject:Information and Communication Engineering
Abstract/Summary:PDF Full Text Request
There are two types of dispersion phenomenon in Photonic crystal. One is spatial dispersion, which is associated with the single frequency electromagnetic waves and can produces spatial dispersion effects such as negative refraction, super-prism and self-collimation. The other is temporal dispersion, also called pulse dispersion, which is associated with many frequencies of electromagnetic pulse. The maximum value of pulse dispersion in photonic crystal is roughly equivalent to two orders magnitude more than that of the ordinary single-mode fiber. Coupled with photonic crystal devices small size and light weight advantages, pulse dispersion in photonic crystal is becoming a research hotspot in recent years. This paper mainly researches the dispersion characteristics and regulation mechanism of two-dimensional photonic crystal. The main contents of this paper are as follows:First of all, the current research and characteristics of the dispersion in two-dimension photonic crystal and metallic photonic crystal are described, and then the numerical calculation method of photonic crystal is introduced in detail, such as the plane-wave expansion method, which is used to analyze the band structure of the photonic crystal, the parabolic approximation method and the least-squares spline approximation method, which are used to analyze the photonic crystal dispersion characteristics, and the finite-difference time-domain method which is used to simulate the normal and dispersion photonic crystal.Second, the dispersion parameter of two-dimensional photonic crystal is investigated in analytic theory and numerical simulation. The dispersion mechanism and type of photonic crystal dispersion are introduced and analyzed in detail by establishing theoretical model. The dispersion parameter of photonic crystal is obtained by analyzing the photonic band structure, using the least-squares spline approximation method which has a little high precision. The effect of various factors on the pulse propagation is analyzed by introducing a weighting factor in finite-difference time-domain method.Finally, the dispersion regulation mechanism of two-dimensional photonic crystal is investigated. Analysis of the cylinder radius and the dielectric constant of the normal dispersion photonic crystal shows, as the radius and dielectric constant of photonic crystal increase, the band structure curve shifts down, which makes the center frequency of pulse shift up. On the contrary, the center frequency of pulse may fall into the band gap and the propagation of pulse will be stopped in photonic crystal. In addition, analysis of the embedded radius of the Cu metallic photonic crystal shows, as the embedded radius of the Cu metallic photonic crystal increases, the pulse width will be increased in some degree, and the high order dispersion can also be decreased. However, as the embedded radius increases to a certain value, the pulse width will be somewhat compressed, the high order dispersion will be tended to increase. If the embedded radius continues to increase, the pulse will begin to split for the reason that metal has strong dispersive effect.
Keywords/Search Tags:Photonic Crystal, Group Velocity Dispersion, Metallic Photonic Crystal, Pulse Propagation, Finite-Difference Time-Domain Method
PDF Full Text Request
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