Ge2Sb2Se4Te on n=1 ITO: a monolithic platform for integrated photonics with mode symmetrization and post-fabrication tuning [Invited]

We demonstrate, to our knowledge, a novel monolithic platform for photonic integrated circuits (PICs) based on amorphous-Ge2Sb2Se4Te (am-GSST). Additionally, we explore the concept of mode symmetrization using the epsilon-near-zero behavior displayed by indium-tin-oxide (ITO) to achieve a substrate with n = 1 at 1550 nm, the same as the air cladding. We designed, fabricated, and characterized various on-chip components using this platform, including waveguides with preliminary 5.57 +/- 0.365 dB/mm propagation loss. Furthermore, we propose a post-fabrication tuning of the refractive index by using the phase change nature of GSST to crystallize local sections of the waveguides using electron beams. Our substrate-blind approach is a versatile platform for post-fabrication tunable PICs that could benefit intricate on-chip nanophotonic structures requiring enhanced and symmetric mode confinement. (c) 2024 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.