Waveguides composed of electromagnetically-coupled optical microcavities(coupled resonator optical waveguides or CROWs) can be used for light guiding,slowing and storage. In this paper, we present a two-dimensional analysis offinite-size straight and curved CROW sections based on a rigorous Mullerboundary integral equations method. We study mechanisms of the coupling ofwhispering gallery (WG) modes and guiding light around bends in CROWs composedof both identical and size-mismatched microdisk resonators. Our accurateanalysis reveals differences in WG modes coupling in the vicinity of bends inCROWs composed of optically-large and wavelength-scale microcavities. Wepropose and discuss possible ways to design low-loss CROW bends and to reducebend losses. These include selecting specific bend angles depending on theazimuthal order of the WG mode and tuning the radius of the microdiskpositioned at the CROW bend.
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