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PIERS Online
Vol. 4
No. 5
2008
pp: 506-510Coupling Theory of Asymmetric Photonic-crystal WaveguidesChih-Hsien Huang, Wen-Feng Hsieh, and Szu-Cheng Cheng doi:10.2529/PIERS071215034736 Downloads: 647 Abstract:The physical properties of asymmetric photonic-crystal directional couplers are studied by using the tight-binding theory, which considers that the field distributions of photonic-crystal waveguides (PCWs) are localized around the periodic defects. From this model, the analytic formulas which describe the dispersion of the coupler and the eigenmode patterns were derived. By considering coupling up to the third nearest-neighboring between two PCWs, analytic expressions of the dispersion relations of asymmetric photonic crystal coupler are consistent with the results from the plane wave expansion method (PWEM). Due to the broken symmetry, two dispersion curves will never cross. Nevertheless, the eigenmode patterns switch their parity as the symmetric coupler does when wavevector k passes over the decoupling point.References:1. Kashani, Z. G., N. Hojjat, and M. Shahabadi, "Full-wave analysis of coupled waveguides in a two-dimensional photonic crystal," Progress In Electromagnetics Research, Vol. 49, 291-307, 2004. 2. Chien, F. S. S., J. B. Tu, W. F. Hsieh, and S. C. Cheng, "Tight-binding theory for coupled photonic crystal waveguides," Phys. Rev. B, Vol. 75, 125113, 2007. 3. Christodoulides, D. N. and N. K. Efremidis, "Discrete temporal solitons along a chain of nonlinear coupled microcavities embedded in photonic crystals," Opt. Lett., Vol. 27, 568, 2002. |
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