Improved analysis for the coupling characteristics of two rectangular dielectric waveguides laid in different layers

A coupled-mode theory proposed by A. Hardy and W. Streifer (J. Lightwave Technol., vol.3, p.1135-46, 1985) and step-like approximation are used in this analysis. Comparison between the present result and the previous one indicates that the present approach is more useful, especially in case of strong coupling.<
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