Planar Scale Invariant Waveguides and Resonators with Uniform Air Confined Modes

TL;DR

This paper introduces a planar metamaterial resonator and waveguide with scale-invariant, air-confined modes on an SOI platform, enabling high-quality light confinement and robust integrated photonics applications.

Contribution

It presents a novel scale-invariant waveguide design with uniform air-confined modes, validated by simulations and experiments, and demonstrates high-Q racetrack resonators compatible with CMOS fabrication.

Findings

Effective index remains constant across widths

Achieved quality factor of 40000 in resonators

Confirmed scale invariance through measurements

Abstract

We demonstrate a planar metamaterial based resonator and waveguide with strong light confinement in air based on a silicon-on-insulator (SOI) platform that exhibits scale invariance in the lateral direction. By embedding a sub wavelength grating (SWG) region between two silicon ridges, the waveguide maintains a nearly constant effective index across varying widths while sustaining a uniform field distribution. Simulations and experimental measurements using Mach Zehnder interferometers confirm scale invariance, and racetrack resonators fabricated from the same structure exhibit an intrinsic quality factor of 40000. The ability of the resonance based structures for confining light in air, providing large interaction regions with high quality factors along with compatibility with CMOS fabrication processes and robustness against fabrication imperfections make them excellent candidates for enhanced light matter interaction applications with improved power handling, offering a promising platform for integrated photonics.