Frozen mode in coupled single-mode waveguides with gratings

TL;DR

This paper introduces a systematic method for designing slow-light photonic circuits using stationary inflection points in coupled waveguides with gratings, demonstrating practical fabrication and potential for integrated delay functionalities.

Contribution

The paper presents a novel design approach for frozen mode in coupled waveguides utilizing exceptional points of degeneracy, validated through fabrication and simulation.

Findings

Successful design of SIP-based slow-light waveguides

Fabricated waveguides show good agreement with simulations

Feasibility of integrating delay functionalities in silicon photonics

Abstract

We present a systematic methodology for designing slow-light photonic integrated circuits with a frozen mode based on a special kind of exceptional point of degeneracy (EPD) of order three named stationary inflection points (SIPs). This is realized through three-way coupled waveguides with lateral gratings operating at telecommunication wavelengths. We provide two designs and analyze sensitivity to geometric perturbations. We have fabricated a periodic waveguide with integrated taper loads and demonstrate reasonable agreement with full-wave simulations. These findings confirm the feasibility of integrating SIP-based delay functionalities in standard silicon photonic platforms.