تحليل الكترومغناطيسي موجبرهاي مبتني بر گاف فوتوني

چكيده انگليسي :

Electromagnetic Analysis of 2D Photonic Band Gap Waveguides Fatemeh Fani Sani f fanisani@ec iut ac ir Date of Submission 2010 01 02 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Amir Borji aborji@cc iut ac irAbstractDuring the past few decades applications of photonic crystals have been rapidlyexpanding Photonic crystals are periodic dielectric or metallic structures that aredesigned to control and manipulate the propagation of light As in normal crystal latticewhere the periodic arrangement of atoms lead to energy band gap the periodicdistribution of dielectric or metallic inclusions creates frequency ranges in whichpropagation of electromagnetic waves is prohibited It means the wave whose frequencyfalls within the band gap regardless of its wave number exponentially decays in photoniccrystal The properties which control the behavior of light become photonic crystal bewidely used in future optical circuits and devices such as modulators optical couplers semi conductor lasers and filters and so on The aim of this thesis is to specify the properties and band diagram of photonicwaveguides At first the characteristics of two dimensional 2D photonic crystals in thepolarization of TE and TM are obtained It is denote that the band structure depends onthe specific geometry and composition of the photonic crystal such as the lattice size theshape and size of lattice elements and the contrast in refractive index Various analytical or computational techniques have been developed to formulate theelectromagnetic scattering guiding and coupling problems in periodic structures Weapply Plane Wave Expansion PWE method to modeling the properties of photoniccrystals and related optical devices In PWE method Maxwell s equations aretransformed into the eigenvalue problem from which dispersion characteristics of theperiodic structure are extracted Calculating photonic band structures of periodic systems containing dispersive and highlyabsorptive material which has frequency dependent dielectric function with or withoutimaginary part led to the generalize eigenvalue problem To calculate the photonic bandstructure of these systems we employ a standard linearization technique which solves thegeneral nonlinear eigenvalue problem by diagonalization of an equivalent enlargedmatrix The use of complex dielectric function results in complex frequencies that theimaginary part determines the lifetime of the wave Even though 3D photonic crystals can have complete band gaps and can confine light inall three dimensions but the hardship of their fabrication led to use of simple structures Periodic dielectric waveguides which have only a one dimensionally periodic pattern orgrating along the direction of propagation but have a finite thickness are such simplifiedstructures Calculating the band structure of grating is obtained by use of supercelltechnique This method is a generalized method of PWE and is used for structures that

فاني ثاني، فاطمه

تحليل الكترومغناطيسي موجبرهاي مبتني بر گاف فوتوني

بلور فوتوني , روش PWE , موجبرباديواره تناوبي , نمودار پاشندگي