Ultra-miniaturized crossings based on digitized metamaterials for one-dimensional grating waveguides

Abstract

The challenge of designing crossings in one-dimensional grating waveguides (1DGWs) arises from the noticeable asymmetry in Bloch mode profiles, which causes the guided modes to be compressed toward the outer sidewall. The proposed solution involves using digitized metamaterials in an extensively corrugated 1DGW on a silicon-on-insulator platform. The resulting crossing structure has an ultra-miniaturized and ultra-low loss design, with a broad bandwidth spanning from 1500 to 1580 nm, while maintaining a minimal footprint of merely 2.1×2.1 µm2. The fabricated device is found to have an insertion loss of -2.52 dB within the wavelength range of 1500 to 1580 nm. This design represents a significant advancement in the pursuit of compact and low-energy silicon photonic waveguide crossings. © 2024 SPIE.