Waveguiding and losses in photonic crystals based on suspended membranes

Abstract

We perform the modelling of a PC waveguide embedded in a membrane with refractive index of 3.2 suspended in air. Due to the index contrast between the membrane and the surrounding air, a good confinement of light inside the membrane is obtained. The 2D PC consists of a triangular lattice of air holes drilled through the membrane. A single line waveguide is obtained by removing a row of first neighbor holes, which introduces an extended linear defect in the periodic structure responsible for the emergence of electromagnetic modes inside the gap. To study the dispersion curves and the spatial distribution of the electromagnetic modes appearing in the waveguide. 3D calculations are necessary to take into account the finite height of the membrane and the occurrence of vertical losses.