Semi-elliptical dielectric-loaded surface plasmon-polariton waveguides

Semi-elliptical dielectric-loaded surface plasmon-polariton waveguide (DLSPPW) is proposed. The mode effective index, field confinement, and propagation length of the fundamental mode supported by it are calculated at the telecom wavelength λ = 1.55 μm for different dimensions of a polymer ridge (with the refractive index of 1.535) placed on a gold film surface. The waveguide structure is found to exhibit 23% increase of the propagation length while showing similar confinement as compared to conventional rectangular DLSPPW when ridge thickness t < 450 nm (ridge width w = 600 nm) and ridge width w < 320 nm (ridge thickness t = 600 nm).

Research Highlights►We demonstrate an increase of propagation length by changing the shape of ridge. ►Semi-elliptical DLSPPW is proposed. ►The propagation length are calculated at ?=1.55?m for different dimensions. ►The waveguide structure exhibits much increase of the propagation length.