Analysis of optical fiber directional coupling based on theHE11 modes. I. The identical-core case |
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Authors: | Horng Shou Huang Hung-Chun Chang |
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Affiliation: | Dept. of Electr. Eng., Nat. Taiwan Univ., Taipei ; |
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Abstract: | For pt.II see ibid., vol.8, no.6, p.832-7 (1990). The directional coupling between two identical single-mode optical fiber cores is analyzed by using the coupled-mode theory in the vectorial form based on the exact HE11 modes. Analytical expressions for the coupling coefficients and the butt coupling coefficient appearing in the conventional and the recently formulated new coupled-mode equations are presented. The effect of the different polarizations on the coupling is considered. The accuracy of the conventional and new theories as applied to the two-core system is examined by comparing the coupling coefficients with exact numerical values. It is shown that as long as the exact HE11 modes are used, the coupled-mode calculations behave well in predicting the coupling strength beyond the weakly guiding regime, and that the simpler conventional theory can provide satisfactory results when applied in the vectorial form |
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