Nonvolatile Tuning of Bragg Structures Using Transparent Phase-Change Materials

TL;DR

This paper demonstrates the use of a transparent, nonvolatile phase-change material, Sb2Se3, to tune Bragg structures on-chip, enabling dynamic control of optical filtering and resonance without volatility.

Contribution

It introduces a novel application of Sb2Se3 for nonvolatile tuning of Bragg gratings and Fabry-Perot cavities, combining modeling and experimental validation.

Findings

Sb2Se3 can induce broadband transparency with silicon due to similar refractive indices.

Crystalline Sb2Se3 enhances index contrast in Bragg devices.

Experimental results reveal design potential and fabrication challenges.

Abstract

Bragg gratings offer high-performance filtering and routing of light on-chip through a periodic modulation of a waveguide's effective refractive index. Here, we model and experimentally demonstrate the use of Sb2Se3, a nonvolatile and transparent phase-change material, to tune the resonance conditions in two devices which leverage periodic Bragg gratings: a stopband filter and Fabry-Perot cavity. Through simulations, we show that similar refractive indices between silicon and amorphous Sb2Se3 can be used to induce broadband transparency, while the crystalline state can enhance the index contrast in these Bragg devices. Our experimental results show the promise and limitations of this design approach and highlight specific fabrication challenges which need to be addressed in future implementations.