Waveguide Crossing Based on Air-Silicon Effective Medium

Abstract

All-silicon effective-medium-clad waveguides are a candidate for an integrated terahertz platform with high efficiency and broadband functionality. In order to implement dense circuitry, low-loss, low-crosstalk waveguide crossings are necessary. In this work an all-silicon waveguide crossing utilizes Maxwell-Garnet effective medium theory to facilitate mode transformation in the crossing region, resulting in suppressed crosstalk. Results show average insertion loss below 1 dB and average crosstalk level of −40.9 dB across the broad 220–330 GHz band for both in-plane and out-of-plane fundamental modes. With simple, single-step fabrication using deep reactive ion etching, this structure is ideal for integration on mass fabricated terahertz, all-silicon integrated circuits.