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The nanophotonic waveguide is gaining high popularity, because its significance is not only limited to the optical interconnects, but also it has been widely accepted for the sensor, filter, and other applications. The standard height of SOI-based nanophotonic waveguide is around 220 nm, which has already been explored extensively. However, some researchers have recently focused the attention on the reduced height waveguides (of 100 nm). Moreover, the photonic waveguides with the reduced height are suffering from high dispersion phenomena. To overcome this problem, the over-cladding technique, using silicon nitride (Si3N4) material, has been opted in the current work that improves the dispersion characteristics and other waveguide parameters. From the analysis, it has been observed that without the over-cladding layer, the dispersion is around −8000 ps/nm-km. Moreover, utilizing the over-cladding layer of thicknesses 200 nm and 100 nm, the dispersion values have been reduced respectively to around −3300 ps/nm-km and − 2000 ps/nm-km, with their respective strip widths of 500 nm and 800 nm, at the operating wavelength of 1.55 μm. Further, the current work can be extended for the design of optical filters and other related applications. [ABSTRACT FROM AUTHOR]

Various photonic integrated components have been implemented by ultra-thin silicon-on-insulator (SOI) waveguides; therefore, it is desirable to couple ultra-thin SOI waveguides to plasmonic waveguides. In this paper, we present an ultra-thin SOI waveguide to a metal-dielectric-metal plasmonic waveguide based on a lens-funnel structure consisting of truncated Luneburg lens and metallic parabolic funnel. The lens is implemented by varying the guiding layer thickness. The effect of different parameters of the coupler's geometry is studied using the finite-difference time-domain method. The 1.13-μm-long coupler improves the average coupling efficiency in the C-band from 66.4 to 82.1%. The numerical simulations indicate that the coupling efficiency is higher than 69% in the entire O, E, S, C, L, and U bands of optical communication. [ABSTRACT FROM AUTHOR]

Single-mode submicrometer-thick strip waveguides on silicon-on-insulator substrates, fabricated by silicon-planar-technology methods are considered. To solve the problem of 1.5-µm wavelength radiation input-output and its frequency filtering, strip diffraction gratings and two-dimensional photonic crystals are integrated into waveguides. The reflection and transmission spectra of gratings and photonic crystals are calculated. The waveguide-mode-attenuation coefficient for a polycrystalline silicon waveguide is experimentally estimated. [ABSTRACT FROM AUTHOR]

Surface plasmon propagation in a nano metal strip waveguide with a biaxial substrate material was studied. The dispersion of the four fundamental modes propagating in the strip waveguide structure was analysed using a formalism based on the method of lines. The propagation properties of these modes with respect to the thickness of the metal film was studied, with two different biaxial materials as substrate for the waveguide. The results were then compared with the asymmetric strip waveguide structures with isotropic substrate and a uniaxial anisotropic substrate. Propagation characteristics as a function of longitudinal and transverse anisotropic components of the substrate material were also studied. The characteristics of the fundamental modes are observed to vary depending on the anisotropy of the biaxial material used. [ABSTRACT FROM AUTHOR]