Design, simulation, and fabrication of 3D self-collimation photonic crystals

Abstract

In this paper, we present self-collimation in three-dimensional (3D) photonic crystals (PhCs) that consist of a simple cubic structure. By exploiting the dispersive characteristics of the photonic crystals, we demonstrate the ability to achieve structureless (defect-free) confinement of light. We also verify that polarization dependence is a key issue in 3D self-collimation. The results hold promise for the high-density PhCs devices due to the lack of structural interaction. Finally, a novel method for the fabrication of three-dimensional (3D) simple cubic photonic crystal structures using conventional planar silicon micromachining technology is presented. It overcomes the disadvantages of the methods hitherto reported in the literature for the fabrication of 3D photonic crystal devices, which include high complexity of multi-step processes, tight alignment tolerances, long turnaround times, and incompatibility with an integrated photonics platform. The method utilizes a single planar etch mask coupled with time multiplexed sidewall passivating deep anisotropic reactive ion etching along with isotropic etch process to create three-dimensional photonic crystal devices. Initial experimental results are presented.