Demonstration of beta-Ga2O3 Optical Waveguides and the Analysis of Their Propagation Losses in the UV-Visible Spectra

TL;DR

This study demonstrates beta-Ga2O3 optical waveguides on sapphire, analyzes their propagation losses across UV-visible spectra, and identifies key loss mechanisms, highlighting their potential for integrated photonics.

Contribution

First demonstration of beta-Ga2O3 waveguides on sapphire with comprehensive loss analysis and optimization for UV-visible applications.

Findings

Minimum propagation loss of 3.7 dB/cm at 810 nm

Loss mechanisms include two-photon absorption and scattering

Beta-Ga2O3 shows promise for UV-visible photonics

Abstract

This paper reports the first demonstration of beta-phase gallium oxide as optical waveguides on sapphire substrates grown by metal-organic chemical vapor deposition (MOCVD). The propagation losses from visible to ultraviolet spectra were comprehensively studied. By optimizing the fabrication processes, minimum propagation loss was identified to be 3.7 dB/cm at the wavelength of 810 nm, which is comparable to other wide bandgap materials within the III-N family (GaN, AlN). To further reveal the underlying loss mechanisms, several physical mechanisms such as two-photon absorption, sidewall scattering, top surface scattering, and bulk scattering were taken into consideration. The results obtained from this work suggest that beta-Ga2O3 is promising for ultraviolet-visible spectrum integrated photonic applications.