Silicon nanorods-based all-dielectric waveguides with long decay-length at the telecommunication band

We investigate subwavelength waveguides composed of silicon nanorods array in straight and nonstraight regimes deposited on a silica (SiO2) substrate. It is shown that using all-dielectric nanorods with high permittivity to design an all-dielectric optical waveguide provides several advantages such as low-dissipation coefficient and long decay length for the distributed fields. Exploiting silicon arrays in touching and nontouching arrangements, we examined the optical response of the structure to the guiding of magnetic and electric fields with transverse and longitudinal polarization modes. We studied the decay length for all propagated modes in both nanochain orientations numerically. Simulation results for straight arrays showed that the averaged decay length for the structure with dielectric particles in touching regime is 1.6 mu m (for the waveguide with the length of 2.2 mu m), and for the nontouching array is 2.2 mu m (for the array with the length of 3.1 mu m). Calculating transmission loss factors and considering decay length of the proposed waveguide, we verified the strong potential of the proposed structure to design all-dielectric photonic devices to operate at telecommunication spectra (similar to 1310nm and 1550nm). Also, we computed bending losses [dB] for the examined structures based on the bends degree. Copyright (c) 2015 John Wiley & Sons, Ltd.